Abstract: The new assistive standing-up robot followed the rule of sit-to-stand movement was developed. Mathematical model during standing-up motion was built by using Newton-Euler approach for kinetics analysis. Force and moment equilibrium equations were obtained and simulation model was built in Simulink by standing up with robot-aided, robot and arms supported and robot, arm and lower limbs of weakness of muscle strength. By means of assistive standing-up robot and sensors, force and moment were measured and analyzed. The results show that standing-up robot can be efficiently used to assist the rising, especially in initial stage, in spite of sit-to-stand aided-method. Arm-supported standing-up maneuver can keep the posture balance and stable, and has compensation ability of necessary force and moment of lower extremity, particularly close to upright standing posture,and force and moment can be predicted accurately by the standing posture simulation model. Lower limbs of deficient muscle strength play limited role to assist the rising.