After analyzing the working principle of the four-aspect fixed autoblock system, an energy-saving control model was created based on the dynamics equations of the trains in order to study the energy-saving optimal control strategy of trains in a following operation. besides the safety and punctuality, the main aims of the model were the energy consumption and the time error. based on this model, the static and dynamic speed restraints under a four-aspect fixed autoblock system were put forward. the multi dimension parallel genetic algorithm (GA) and the external punishment.function were adopted to solve this problem. by using the real number coding and the strategy of ramps divided into three parts, the convergence of GA was speeded up and the length of chromosomes was shortened. a vector of gaussian random disturbance with zero mean was superposed the mutation operator.the simulation result showed that the method could reduce the energy consumption effectively based on safety and punctuality.