In this paper two kinds of photocapacitance transientes, corresponding respectively to two cases of coupling and uncoupling of two or more deep levels have been studied in detail. According to the great difference of the two kinds of the photocapacitance transientes, a method of determining if two or more deep levels belong to the same center has been suggested. It has some advantages that it can be used to measure the sample including more than two deep levels, the processes are quite simple, and it takes short time to finish a measurement. For example, this method has been used to judge the donor and acceptor levels related to gold in Si. The result has proved that they belong to the same center related to gold in Si.