A unified method for target detection and tracing based on data from sensors of array is presented in order to improve detection and tracking abilities 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 a priori,the status of the targets can be estimated with the maximum a-posteriori(MAP)method directly through the sensors data.The proposed method is different from the classical method,by which it can detect and track targets simultaneously by adding the target’s signal energy information besides its direction of arrival(DOA)information. Simulated and sea trial data results show that the detection and tracing capabilities of weak targets can be improved and wrong tracing and missing tracing problems,which exist in the classical tracing method when it is faced with the crossing targets,can be resolved by the proposed method. A unified method for target detection and tracing based on data from sensors of array is presented in order to improve detection and tracking abilities 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 a priori, the status of the targets can be estimated with the maximum a-posteriori (MAP) method directly through the sensors data. proposed method is different from the classical method, by which it can detect and track targets simultaneously by adding the target’s signal energy information besides its direction of arrival (DOA) information. Simulated and sea trial data results show that the detection and tracing capabilities of weak targets can be improved and wrong tracing and missing tracing problems, which exist in the classical tracing method when it is faced with the crossing targets, can be resolved by the proposed method.