Objective To investigate the effect of foot metatarsophalangeal (MTP) joint constraint on human gait stability. Methods Gait experiment under two states was conducted on a horizontal wet-slip test bench, namely,with and without constraint of the MTP joints. The differences in time-space gait parameters, kinematic parameters, kinetic parameters, and utilization coefficient of friction (UCOF) were analyzed. Results Under the state of MTP joint constraint, the average human walking speed was reduced by 50 mm / s, the stride length was reduced by 0. 22 m, and the double support phase time was shortened by 70 ms. MTP joint constraint resulted in a significant increase in the range of motion (ROM) of the hip and knee in sagittal plane and a decrease in the ROM of the ankle. Meanwhile, the UCOF amplitude with MTP joint constraint was 1. 15 times higher than that without MTP joint constraint, indicating an increased probability of human slip and fall as well as an increased walking instability. Conclusions MTP joint constraint in the foot can reduce walking stability. The results of thisstudy provide data and theoretical support for the development of toe flexion rehabilitation device.