This　paper　examines　the　natural　frequencies　and　modes　of　cracked　Mindlin　plate　using　the　Ritz　method　based　on　the　Mindlin　plate　theory.　The　vibration　characteristics　of　cantilever　Mindlin　plate　with　a　side　crack　are　presented,　and　the　effect　of　the　side　crack　on　the　natural　frequencies　and　modal　function　of　Mindlin　plate　is　also　investigated.　In　this　analysis,　a　special　mode　shape　function　composed　of　two　parts　is　employed,　where　one　part　is　the　ideal　mode　shape　of　intact　Mindlin　plate　obtained　by　the　beam　function　combination,　and　the　other　part　is　the　corner　function　which　uses　the　vertex　singularity　theory　to　construct　the　expression　of　deflection　and　rotation　discontinuity　along　the　crack.　The　results　of　the　Mindlin　theory　obtained　by　a　high-precision　numerical　software　of　Maple　is　then　compared　and　verified　against　the　data　from　finite　element　simulation　by　ANSYS.　©　2018　Journal　of　Dynamics　and　Control.　All　rights　reserved.