With the development and maturity of power semiconductor devices and power electronic devices, the application of DC technology in power system distribution network has received more and more attention. In this paper, the mathematical model of the components loss of DC distribution network is established. The feasibility of component model is analyzed by PSCAD simulation technique and the calculation parameters of component loss are selected to analyze the loss of AC and DC distribution networks and their components under different proportion DC load The potential of the DC distribution network to replace the AC distribution network is given from the point of view of energy consumption. The results show that the DC loss rate of the DC distribution network is lower than that of the AC distribution network with the DC load ratio of 50% ~ 60%, and the proportion of the DC load is heavier. The DC distribution network has better energy saving than the AC distribution network effect.