Pipe leakage may cause environmental pollution, property losses and casualties. It is very important to detect in time and accurately locate pipe leakage for its concealment. There are two issues remained to be settled better in testing: the dispersion phenomena of acoustic emission stress wave induced by pipe leakage, the contradiction between cost (time cost and number of sensors) and precision in leakage testing of pipe network. Concerning these two issues, the corresponding summarization at home and abroad are introduced emphatically, including modal acoustic emission testing technique for continuous and burst type pipe leakage and pipe network leakage testing such as isolation of leakage source, arrangement of sensors and algorithm. The difference and relationship of the previous relevant literatures are combed through in detail. Finally, the deficiencies of present research are discussed and future research objects on these two issues are proposed.