Abstract: An improved time difference mapping method is proposed to locate the acoustic emission (AE) source of composite plate in order to solve the problems of fiber fracture,the matrix crack defects within composite plate and the acoustic velocity in different propagation direction is inconsistent and difference.This method use the prebuilt database method,avoiding consider the propagation speed of waves in the plate are not consistent and the wave propagation modes,and layout of the sensor in experiments is not strictly required.Firstly,in order to quickly and accurately select and delete the pseudo AE events from a large number of AE data,the clustering algorithm is used to automatically identify and select the highly correlated AE events on each grid node and construct a time difference training database.Secondly,interpolation compensation algorithm is adopted to increase grid density and improve grid resolution.Finally,the location of the source is verified by using the weighted difference algorithm to verify the location of the actual source in the test area.Theoretical analysis and experimental results show that the average actual errors of the location of the sound source is reduced from 26.5 mm (using the traditional time difference mapping method) to 18.0 mm (using the improved time difference mapping method),the corresponding average relative error is reduced from 5.3% to 3.6%,and the overall running time is reduced from 5 h to 16.87 s.The research shows that the improved time difference mapping method can effectively improve the location results and precision of the sound source.