Rollover and jack-knifing of tractor semi-trailer are serious threats for vehicle safety,and accordingly active safety technologies have been widely used to reduce or prevent the occurrence of such accidents.However,currently tractor semi-trailer stability control is generally only a single hazardous condition (rollover or jack-knifing) control,it is difficult to ensure the vehicle comprehensive stability of various dangerous conditions.The main objective of this study is to introduce a multi-objective stability control algorithm which can improve the vehicle stability of a tractor semi-trailer by using differential braking.A vehicle controller is designed to minimize the likelihood of rollover and jack-knifing.First a linear vehicle model of tractor semi-trailer is constructed.Then an optimal yaw control for tractor using differential braking is applied to minimize the yaw rate and lateral acceleration deviation of tractor,as well as the hitch articulation angle of tractor semi-trailer,so as to improve the vehicle stability.Second a braking scheme and variable structure control with sliding mode control are introduced in order to achieve the best braking effect.Last Fishhook maneuver is introduced to theactive safety simulation and the active control system effect verification.The simulation results show that multi-objective stability control algorithm of semi-trailer could improve the vehicle stability significantly during the transient maneuvers.The proposed multi-objective stability control algorithm is effective to prevent the vehicle rollover and jackknifing.