Dynamic　effects　are　very　important　to　improving　the　design　of　compliant　mechanisms.　An　investigation　on　the　dynamic　characteristics　of　compliant　mechanisms　is　presented.　The　dynamic　model　of　compliant　mechanisms　is　developed　at　first.　The　natural　frequencies　and　modes,　elastic　motion　response,　sensitivity　analysis,　and　strain　response　of　compliant　mechanisms　are　then　studied　based　on　the　dynamic　model.　Finally,　the　numerical　results　show　the　accuracy　of　the　finite　element　method　for　dynamic　modeling　of　compliant　mechanisms,　and　the　dynamic　characteristics　are　illustrated　clearly.