Objective：To discusses the rationality of the calculation results of the three link model used in the dynamic analysis of squat motion interaction, and clarifies the source of the difference between the three link model and the visual 3D calculation of joint torque. Methods：8 subjects were selected to obtain the kinematic data of squat motion through Vicon. The second kind of Lagrangian equation was used to establish the three-link dynamic equation. The joint torque was calculated based on the Mathematica. The results were compared with the calculation results of Visual3D lower limb chain segment model, and the similarity between the two was evaluated by the coefficient of complex correlation (CMC). Results：The CMC of hip joint and knee joint of 8 subjects were greater than 0.85, and the CMC of ankle joint was between 0.5-0.85. The joint torque calculated by three-link dynamic equation and Visual3D was highly similar at hip joint and knee joint, and only showed moderate similarity at ankle joint. Conclusions：The three-link model can be used in the further analysis of interactive dynamics of squat, but the influence of interaction moment caused by GRF (external moment) on ankle torque should be considered.