Abstract: To solve the problem of valve leakage fault, parallel piezoelectric array based method is proposed for locating acoustic emission source caused by valve leakage. According to the surface characteristics of valve structure, two parallel linear sensor arrays are arranged at the bottom, and each sensor array contains 2M PZT. Firstly, parallel piezoelectric array is used to collect the acoustic emission signal when the valve leaks. Secondly, the covariance of each array was calculated and corresponding eigenvalues were decomposed, and hence the approximate area of acoustic emission signal source was determined by comparing their eigenvalues. In addition, results by spatial spectral estimation using the near-field multiple signal classification algorithm were obtained and the peak of spatial spectral was assumed to be related with the acoustic emission source coordinate. Finally, the polar coordinates in the local coordinate axis were transformed into the global coordinate. The experimental results of DN50 gate valve show that this method can locate the valve acoustic emission source accurately, which can reduce the misjudgment of valve leakage failure, and provide guidance for the prediction of valve failure.