A computational modeling and simulation method for multi-posture gymnastics jump based on sport biomechanics was improved. Taking tuck jump, pike jump and arched jump as examples, the entire jump phase was seperated into four parts: taking off from bending the knees, airborne, posturing and landing. Then the formulas were developed for modelling. Finally, computational simulation experiment was done with the formulas. The simulation outcomes showed that this method is effective in multi-posture gymnastics jumps analysis.