The invention discloses an urban gas pipe network leakage detecting system based on a centerless ad-hoc network, and relates to the technical field of leakage detection. A gas leakage detecting component is connected with intelligent control nodes. A mobile terminal is connected with the intelligent control nodes. The gas leakage detecting component is arranged above a gas pipeline and is closelyadjacent to the gas pipeline, and the two ends of the gas leakage detecting component extend to the positions of a station, pressure adjusting stations (boxes) and a gate well to be disconnected. Theintelligent control nodes are arranged at the positions of the station, the pressure adjusting stations or the pressure adjusting boxes and the gate well. The mobile terminal achieves human-machine interaction. A valve electric executing device is used for controlling opening and closing of an electromagnetic valve. According to an urban gas pipe network leakage detecting method based on the centerless ad-hoc network, a whole is divided into a plurality of areas, the centerless network is formed, and on the basis of the wavelet analysis and approximate entropy and correlation analysis combination method, detection is conducted. The urban gas pipe network leakage detecting system and method have the beneficial effects that when accidents happen, the fault position information can be rapidlyprepared and calculated according to correlation of gas leakage conveying detection components, and emergency measures are triggered.