To consider the problem of collision avoidance and stability when planning the emergency collision avoidance path of lateral lane under high speed scenarios，a path planning algorithm based on non-uniform B-spline curve is proposed，which meets the requirements of multi-constraint. The proposed collision-free path model constructed by two non-uniform B-spline curves has continuous curvature with trapezoidal change and satisfies the slope and curvature constraint at the starting point and end point; and then，the environmental information is combined to generate a collision-avoidance path cluster whose path shape is controlled by two parameters. On this basis，a passenger comfort objective function is constructed，aiming to select a local path with the best comfort from the path cluster when the collision avoidance requirement is met. Furthermore，the objective function and multi-constrains of the vehicle are used to obtain the optimized longitudinal acceleration so as to complete the collision avoidance motion planning. Finally，the model predictive control (MPC) algorithm specialized in multi-constrained problem is selected to develop a linear time-varying MPC controller，and the feasibility of the proposed path planning method is verified.