Lotus seed is a kind of nourishing food, which can be eaten and used medicinally. The fresh lotus seed is mainly composed of lotus shell, lotus kernel, lotus seed coat, lotus core, etc. The lotus shell is wrapped in the outside of the lotus kernel, and the lotus seed coat is tightly attached to the surface of the lotus kernel, while the lotus core grows in the inside of the lotus kernel. In order to improve the taste, the seed coat usually should be removed before eating due to the bitter astringent taste. However, the lotus seed coat is very difficult to be removed, and manual peeling is laborious. A fresh lotus seed peeling machine was designed based on water jet. To improve the operation performance of the machine, the operation parameters of the peeling machine were studied. The water jet pressure, water jet angle and the processing speed were chosen as the main factors, and the peeling rate, damage rate, with head rate, openside rate and drop rate were chosen as the main evaluation indicators. The three-factors and three-level response surface was designed by the Design-Expert software. The test results was showed as follow: considering the effect of peeling rate, damage rate and with head rate, the degree order of influence from big to small was water jet pressure, water jet angle and processing speed;considering the effect of openside rate, the degree order of influence from big to small was water jet angle, water jet pressure and processing speed, but the effect of processing speed on the openside rate was very small;these test factors had almost no effect on the drop rate, and the drop rate was almost 1%, which was perhaps caused by other unknown factors. The optimal operating parameters of the machine were as follows: the water jet pressure was 0.7MPa, the water jet angle was 18°, and the pulley diameter was 68mm. The predicted value was as follows: the peeling rate was 91.16%, the damage rate was 0.96%, the with head rate was 2.40%, and the openside rate was 0.04%. The machine was adjusted to the optimized parameters for verification tests, the peeling rate was 92.63%, the damage rate was 1.24%, the with head rate was 2.72%, and the openside rate was 0.21%. Comparing the above results, it can be seen that the absolute errors of the experiment results and theoretical optimization results were controlled within a relatively small range, which verified the rationality of the model and the optimized parameters, these work would provide a theoretical basis for the performance improvement of fresh lotus peeling machine.