The leaking of water pipes will not only waste a large amount of water but also cause great economical damage. This paper is about the research on the leaking detector based on DSP. At first, the leaking detector can collect sound signals that flow two sides by pressure sensors fixed at the two sides of the water pipes, then it will enlarge and remove the noise of the collected sound signals. At last, with the assistance of relative information about signals, it can find out the exact leaking position. Having passed physical verification, this leaking detector can figure out the exact location of water pipe leaking.