In order to reduce such accidents as the rear-end collision and side scraping when vehicles enter the exit of interchange， a theoretical calculation model of the outflow angle of deceleration lane was established to analyze the influence of stopping sight distance on the outflow angle range of interchange deceleration lane at different design speed. Furthermore， the vehicle dynamics simulation model was set up by using CarSim to sim- ulate the process of vehicles entering the exit of interchange. Finally， from the perspective of anti-sliding and anti-overturning of the vehicle， the lateral stability of the vehicle during driving was analyzed so as to verify the rationality of the calculation model of the outflow angle.