Abstract: A unified method for target detection and tracking based on data from sensors of array is presented in order to improve the detection and tracking ability of the weak targets with low signal-to-noise ratio.Assuming that the multiple targets are uncorrelated each other and the number of the targets is known as a prior,then the status of the targets can be estimated with the Maximum A-Posteriori(MAP)method directly through the data from sensors of array. The proposed method is different from the classical method in that it can detect and track targets simultaneity based on energy and information about Direction of Arrival(DOA).Simulation results show that the detection and tracing capabilities of the weak targets can be improved and the wrong tracing and the missing tracing,which lies in the general tracing method when it comes to the cross targets,can be solved with the proposed method.The real trail results show that the proposed method is of practical engineering value.