Movement trajectory identification is a hot topic in robot research field, this paper uses least square to study the movement trajectory of the gait robots, measures and calculates the characteristic parameters of human gait, based on this, uses curve fitting method to set up the corresponding mathematical models for each joint position of lower limbs, receives the overall mathematical model of gait robot movement trajectory, and finally uses the received mathematical model formula to prove the feasibility and validity of the research methods held by this paper.