Based　on　the　direct　differential　method,　a　sensitivity　analysis　method　for　the　dynamic　characteristic　of　flexible　parallel　robots　was　presented.　Compared　with　finite　difference　method,　the　result　of　sensitivity　is　more　precise.　The　method　can　also　be　used　to　estimate　the　numerical　value　of　dynamic　characteristic　with　the　perturbation　of　design　parameters,　without　carrying　out　Kineto-Elastodynamics　analysis.　The　simulation　shows　that　the　method　is　accurate　and　efficient.　The　dynamic　characteristic　is　sensitive　to　the　variation　of　the　cross-sectional　area　of　the　framed　links,　lumped　mass　attached　to　links　and　the　thickness　of　the　links.　The　sensitivity　analysis　for　dynamic　characteristic　is　demonstrated　to　have　significant　impact　on　Kineto-Elastodynamics　synthesis　and　the　optimal　design　of　flexible　parallel　robots.