Five asymmetrical soft robot hands are designed for the stable picking of fruit and vegetables, and optimized. The evaluation indicators were proposed for the analysis of the threedimensional(3D) deformation of fingers in lateral grasping with multifingered soft hands at different load masses. The indicators included the minimum working pressure, the distortion angle of finger and the vertical displacement of finger. Through the test of the deformation of a single finger with no load at different working pressures and the test for the five multifingered robot hands in different loads and at different working pressures, the change of deformation of fingers in different working conditions were derived. The results indicate that the robot hands with asymmetrically placed fingers show less increase in the minimum working pressure and deformation when higher load is imposed. For the conditions involved, the vertical movement at end of fingers are more sensitive to changes of loads, and higher working pressure is beneficial for the stable gesture of soft robot hands. Generally, the performance of the fourfingered humanoid hand is the best by comparison. These findings will provide a reference for the design optimization and precise control of soft grippers.