The backward tracing method of the shortest path ray tracing algorithm with dynamic networks can solve the unstability problem in the backward tracing procedure of the LTI (Linear Travel-time Interpolation) algorithm, but the computational efficiency of the method is low. This study presented an improved method on backward tracing. According to the location information of the secondary sources for the nodes and the law of wave propagation, a large number of redundancy calculation are excluded in the backward tracing of the dynamic networks tracing algorithm. The numerical examples show that the improved method exhibits the higher computational efficiency. The calculation efficiency of the improved method is several times that of the backward tracing method of the dynamic networks tracing algorithm. When the improved method is applied to the improved algorithm of the shortest path ray tracing with dynamic networks, the computational efficiency of the algorithm can be increased by about 100 %.