In the multi-response optimization design of 3-RRR compliant parallel micromotion platform, there are various factors influencing and interactive influencing conditions, which lead to the flexibility instability. In order to solve this problem,a new design method to optimize the flexibility robustness of the mechanism was proposed by combining the cluster analysis with the response surface method.A multi-directional flexibility kinematic model of the hinge of the micromotion platform was established, and then the experimental design and cluster analysis were carried out. The response surface method was introduced to construct the response surface model and particle swarm optimization algorithm was used to find the optimal solution. According to the evaluation result of signaltonoise ratio (SNR) index, the robust optimization design scheme satisfying the constraint conditions was obtained. The example shows that the clustering analysis method can provide a new method for flexible hinge multiobjective robust optimization design with good results