During the process of design for testability (DFT), the procedure of test points addition is significantly time-consuming especially when systems become complex. To resolve this problem, an efficient method to allocate test points based on multi-signal flow graph is proposed in this paper. First, the dependency matrix that describes the relationship between signals and candidate test points is presented assuming that each output of modules in the multi-signal flow graph is considered as a candidate test point. Thus, the test point allocation problem can be formalized as searching for the optimal candidate test point set to detect and isolate the signals. Then, genetic algorithm is applied on the dependency matrix to search for the optimal test point set. Finally, the proposed method is examined by a multi-signal flow graph. The result shows that the proposed method can allocate the optimal test points in acceptable time.