<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN ActiveDisclosure(SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2021-10-23T01:53:50.1834367+00:00 -->
<!-- Version            : 5.0.1.702 -->
<!-- Package ID         : d46884e443a14247ace627848b9dfc3e -->
<!-- Copyright (c) 2021 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema xmlns:dei="http://xbrl.sec.gov/dei/2021" xmlns:us-types="http://fasb.org/us-types/2021-01-31" xmlns:stpr="http://xbrl.sec.gov/stpr/2021" xmlns:srt-types="http://fasb.org/srt-types/2021-01-31" xmlns:exch="http://xbrl.sec.gov/exch/2021" xmlns:sic="http://xbrl.sec.gov/sic/2021" xmlns:caty="http://www.cathaybank.com/20211025" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:srt="http://fasb.org/srt/2021-01-31" xmlns:enum2="http://xbrl.org/2020/extensible-enumerations-2.0" xmlns:us-gaap="http://fasb.org/us-gaap/2021-01-31" xmlns:naics="http://xbrl.sec.gov/naics/2021" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:country="http://xbrl.sec.gov/country/2021" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:currency="http://xbrl.sec.gov/currency/2021" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2020-01-21" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.cathaybank.com/20211025" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance" />
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase" />
  <xsd:import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt" />
  <xsd:import schemaLocation="https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd" namespace="http://xbrl.org/2020/extensible-enumerations-2.0" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/country/2021/country-2021.xsd" namespace="http://xbrl.sec.gov/country/2021" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/currency/2021/currency-2021.xsd" namespace="http://xbrl.sec.gov/currency/2021" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/dei/2021/dei-2021.xsd" namespace="http://xbrl.sec.gov/dei/2021" />
  <xsd:import schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd" namespace="http://www.xbrl.org/dtr/type/2020-01-21" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/exch/2021/exch-2021.xsd" namespace="http://xbrl.sec.gov/exch/2021" />
  <xsd:import schemaLocation="http://www.xbrl.org/lrr/arcrole/factExplanatory-2009-12-16.xsd" namespace="http://www.xbrl.org/2009/arcrole/fact-explanatoryFact" />
  <xsd:import schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd" namespace="http://www.xbrl.org/2009/role/negated" />
  <xsd:import schemaLocation="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd" namespace="http://www.xbrl.org/2009/role/net" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/naics/2021/naics-2021.xsd" namespace="http://xbrl.sec.gov/naics/2021" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/sic/2021/sic-2021.xsd" namespace="http://xbrl.sec.gov/sic/2021" />
  <xsd:import schemaLocation="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd" namespace="http://fasb.org/srt/2021-01-31" />
  <xsd:import schemaLocation="https://xbrl.fasb.org/srt/2021/elts/srt-roles-2021-01-31.xsd" namespace="http://fasb.org/srt-roles/2021-01-31" />
  <xsd:import schemaLocation="https://xbrl.fasb.org/srt/2021/elts/srt-types-2021-01-31.xsd" namespace="http://fasb.org/srt-types/2021-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/stpr/2021/stpr-2021.xsd" namespace="http://xbrl.sec.gov/stpr/2021" />
  <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd" namespace="http://fasb.org/us-gaap/2021-01-31" />
  <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2021/elts/us-roles-2021-01-31.xsd" namespace="http://fasb.org/us-roles/2021-01-31" />
  <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2021/elts/us-types-2021-01-31.xsd" namespace="http://fasb.org/us-types/2021-01-31" />
  <xsd:annotation>
    <xsd:appinfo>
      <link:roleType id="TemplateLink" roleURI="http://www.cathaybank.com/20211025/role/TemplateLink" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>00000 - Document - Template Link</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="caty-20211025_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:title="Label Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="caty-20211025_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation Links, all" xlink:type="simple" />
      <link:roleType roleURI="http://www.cathaybank.com/20211025/taxonomy/role/DocumentDocumentAndEntityInformation" id="Role_DocumentDocumentAndEntityInformation">
        <link:definition>100000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
</xsd:schema>
