To　analyze　large　deflection　beams　with　inflection　point　in　compliant　mechanisms,　a　dynamic　model　of　the　compliant　mechanisms　with　inflection　point　was　established,　and　the　kinetic　equations　were　deduced　based　on　the　Lagrange　equation.　The　curves　of　the　angle　of　rotation　were　obtained　in　MATLAB　software　and　compared　with　the　simulation　results　of　ADAMS　software.　Results　show　that　the　rotation　angle　of　the　joint　at　the　inflection　point　varies　significantly　with　the　dynamic　coupling　between　the　rods.　This　reflects　the　difference　between　the　dynamic　model　of　the　compliant　mechanism　with　inflection　point　and　the　dynamic　model　of　the　compliant　mechanism　without　inflection　point.　The　dynamic　model　can　reflect　the　complicated　deformation　and　motion　of　the　compliant　mechanisms　exactly.　©　2018,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.