The invention discloses a pressure distribution reestablishment method based on an equi-potential filter back projection algorithm. The pressure distribution reestablishment method is characterized in that through the characteristic that the resistivity of a pressure pad (1) manufactured by adopting a piezoresistance material changes under pressure, excitation current is injected into the pressure pad (1) by adopting an excitation power supply (2); the edge voltage on the surface of the pressure pad (1) is simultaneously detected; back calculation is carried out by utilizing voltage information and adopting the equi-potential filter back projection algorithm, so that the resistivity variation of the pressure pad is obtained; a force distribution situation of the pressure pad (1) is reestablished according to piezoresistance characteristics of the piezoresistance material. An obtained pressure distribution image can be used for analyzing postures of sitting, standing, walking, lying and the like of a patient, and rehabilitation assistant devices are regulated.