The Wearable Lower Limb Exoskeleton can follow flexible human motion detection data of plantar pressure with human gait feature, so the study of exoskeleton plantar pressure detection system has important significance. There are some nonlinear errors in the input and output of the pressure sensor in the wearable external skeletal system, which can not accurately detect the change of the plantar pressure, Choose resistance type pressure sensor, through the theoretical calculation to determine the curve fitting method is feasible, and the curve fitting method is introduced into the design of the plantar pressure detection system. The research results show that this method has obvious characteristics of the data acquisition, the curve fitting of the system is small, the reliability is high, and it is applicable to the plantar pressure detection system.