ARPS retracts seatbelt webbing by an activating electric motor attached to the seatbelt retractor. FCW is used as a trigger to activate the motor to retract the seatbelt webbing, this makes the occupant restraint system work more effectively in a crash. And it is help for reducing an occupant’s forward movement which results from inertial force acting on the occupant’s body during deceleration in braking. Many experimental results and numerical simulations have been conducted to validate the potential of the ARPS to reduce occupant’s injury. But how can we maximize the potential of an ARPS? This paper will study on pretension performance of ARPS by many static and dynamic experiments, such as pretension force tests, pretension velocity tests, pretension time tests and volunteer experiments. In the last, the rational constraint performance parameters can be obtained.