In order to realize the nondestructive picking of slender fruits and vegetables, a soft pneumatic gripper with aeration and spiral motion was proposed. Based on the finite element static simulation analysis of the gripper, the interaction effect of each factor on the spiral characteristics of the soft pneumatic gripper was studied by using the three-factor and three-level central combination design and response surface analysis method. The quadratic regression model was established with the spiral diameter and pitch of the soft pneumatic grip as the response values, and the determining coefficients of the model were 0.9987 and 0.9351, respectively. The order of significance of the influence of each factor on the spiral diameter and pitch was as follows: wall thickness, cavity width and cavity angle. The simulation diameter of the soft pneumatic gripper was 35mm, and the simulation pitch [50mm,150mm] was taken as the objective function to optimize each influencing factor. The optimal design results were 2.51mm of wall thickness, 30.52° of chamber angle and 11.91mm of chamber height. The results of experiment and simulation showed that the error of screw diameter and pitch was less than 5%. The grasping force of the soft pneumatic gripper was measured under different air pressures, and the results showed that the soft pneumatic gripper had the maximum grasping force of 3.37N at 0.13MPa. Finally, the effectiveness of the soft pneumatic gripper was demonstrated by grasping slender fruits and vegetables of different sizes and softness. Finally, the cucumber was picked as the object, and the cucumber was successfully captured and the stem was broken in 3.6s.