Objective To investigate the biomechanical factors of the lower limbs that affect the mechanical energy of baseball batting. Methods C3D data were collected using a motion capture system and imported into Visual 3D to establish a Hanavan multi-rigid-body human model and a rigid-body model of the bat. Using a prepared pipeline command, the angular velocities and joint torques of the hip, knee, ankle joints, and trunk around the X, Y, and Z axes were calculated and exported. Stepwise multiple linear regression analysis was performed between independent and dependent variables using SPSS, and the factors and dependent variables were incorporated into the regression model. Results The top four independent variables that had the greatest impact on the mechanical energy of the bat were as follows: x19 right ankle joint plantar flexion/dorsiflexion torque (β=91.97), x2 left ankle joint inversion/eversion torque (β=91.74), x25 right hip joint flexion/extension torque (β=91.58), and x3 left ankle joint internal rotation/external rotation torque (β=91.50). Conclusions There was a strong correlation between the right hip joint flexion/extension torque and mechanical work of the bat. The batter transmits energy to the upper limbs by producing a right hip joint extension torque to rotate the trunk and pelvis. There is a close relationship between the adduction and abduction torques of the left ankle joint and mechanical work of the bat, which are used for body braking in the early stages of batting and body rotation in later stages. It is necessary to conduct specific strength training for the adductors of the left ankle joint, extensors of the right hip joint, and plantar flexors of the right ankle joint to enhance batting power.