Objective To provide a theoretical reference for the optimal design of the polisher structure by comparing the differences in the contact parameters of different kinds of rice.Methods Using bench test and simulation test, and combining with MATLAB software image processing technology, the optimal parameter combinations are obtained through the steepest climbing test and quadratic orthogonal test, and the contact parameters of the four kinds of rice grains, namely Japonica Rice, Japonica Glutinous Rice, Indica Rice, and Indica Glutinous Rice, are measured and calibrated.Rseults The coefficient of static friction between Japonica Rice, Japonica Glutinous Rice, Indica Rice, and Indica Glutinous Rice and the steel plate is 0.47, 0.46, 0.52, and 0.52, respectively. The coefficient of rolling friction is 0.069, 0.074, 0.081, and 0.075, respectively. The collision recovery coefficient is 0.40, 0.42, 0.43, and 0.41, respectively. In the stacking angle measurement test, the coefficient of static friction between Japonica rice is 0.34, with a coefficient of rolling friction of 0.04, and a collision recovery coefficient of 0.53. The coefficient of static friction between Japonica Glutinous Rice is 0.32, with a coefficient of rolling friction of 0.04, and a collision recovery coefficient of 0.45. The coefficient of static friction between Indica Rice is 0.37, with a coefficient of rolling friction of 0.06, and a collision recovery coefficient of 0.56. The coefficient of static friction between Indica Glutinous Rice is 0.35, with a coefficient of rolling friction of 0.05, and a collision recovery coefficient of 0.54.Conclusion The coefficients of static friction and rolling friction of the long-grained Indica Rice and Indica Glutinous Rice are larger than those of the round-grained Japonica Rice and Japonica Glutinous Rice. The coefficient of rolling friction of Indica Rice is also slightly larger than that of Indica Glutinous Rice.