The acceleration global performance index of spatial three degreeoffreedom parallel manipulator with redundant actuator was researched by Hessian matrix. The performance atlas was drawn in the default workspace. The geometry size distribution law of spatial three degreeoffreedom parallel manipulator with redundant actuator was analyzed, and the optimal size range under acceleration global performance index was established by the performance atlas. The results show that the best acceleration global performance index ηa is 0803 7 and the corresponding structure parameters are l1=30 m，l2=40 m，l3=05 m，l4=30 m, furthermore the good acceleration global performance areas are 25 m≤l1≤30 m，35 m≤l2≤40 m，05 m≤l3≤10 m，25 m≤l4≤30 m.