Aimed at the reconstructed soft tube for the main circuit of hydraulic pump energy system, a pump supply-oil calculating model is established, and then a pressure pulsating model is built with the help of the resistance regulated method. The difference between the former system without soft tube and the new system is analyzed, this shows that the advantage of reconstruction for the system is obvious, and it is valid for eliminating the overshoot pressure. The results verify that the method mentioned above is valid and feasible. And simultaneously some other methods are presented in this paper also.