Method of backward power flow tracing is proposed for getting the relationship of each power quantity in distribution network. This paper gets power chain containing the relationship between each load and corresponding loss and power stream covering the relationship between each load and extracted power utilizing the theory of power distribution. Load-loss distribution coefficient, and load-extracted power flow distribution coefficient are given in the form of sinusoidal steady-state. This method is adopted to a typical 14-node distribution network, getting the conclusion that the sum of each power quantity equaling to the origin power quantity. Case study shows that in the single source power network, sinusoidal steady-state power follows the principle of impedance matching.