The operation environment of high-speed trains is complex and changeable. The existing target curve of given operation speed mainly considers the safety and punctuality of train operation, which is difficult to improve other operation performance of trains. In order to meet the increasing traffic demand of high-speed trains and improve the running performance of trains, this paper proposes an improved multi-objective speed optimization method for safety, energy saving, punctuality and comfort, considering the optimal adhesion between wheels and rails. First of all, on the premise of meeting the restriction of interval speed limit and train dynamics model, four evaluation indexes of safety, energy saving, punctuality and comfort are established to form a multi-objective optimization model of high-speed train operation process; Secondly, the influence of adhesion between wheel and rail is considered in the energy-saving model, and the traction/braking force is optimized to keep it within the optimal adhesion range, so as to save operating energy consumption; Finally, the non-dominated