The　design　of　a　planar　three-degree-of-freedom　parallel　manipulator　is　considered　from　a　dynamic　viewpoint.　Firstly,　the　dynamic　equations　of　the　planar　three　degree-of-freedom　parallel　manipulator　based　on　the　Lagrange　equation　are　presented.　Then,　three　different　design　measures　are　established　for　the　first　time.　For　example,　selection　proper　balancing　masses　are　added　to　the　system　for　eliminating　the　gravity　and　most　of　the　coupling　terms　from　the　dynamical　equations.　These　design　measures　are　useful　for　improving　dynamic　properties,　controllability,　stability　and　accuracy　of　the　mechanism.　Finally,　an　example　is　given　in　order　to　illustrate　the　effect　of　greatly　reducing　the　required　actuator　torques　and　consumed　energy.　The　analysis　presented,　could　provide　necessary　information　for　dynamic　performance　analysis,　optimization　design　and　control　of　the　parallel　mechanism.　The　method　can　be　easily　extended　to　the　dynamic　analysis　and　design　of　other　multi-linkage　and　multi-degree-of-freedom　mechanisms.