The deviation of microseismic station location will affect the microseismic source location accuracy in microseismic monitoring. The relationship between microseismic station location deviation and source location accuracy is studied in the paper. A global optimization algorithm, particle swarm optimization (PSO), is used to search for the source location. Results show that PSO method is good. The source location error increases with the microseismic station location error. The relationship between them is nonlinear. The microseismic sources outside the microseismic station array are more sensitive to the microseismic station location deviation than inside the microseismic station array. The bigger the microseismic station location error, the greater the difference. Therefore, when the microseismic source is outside the microseismic station array, it is more necessary to ensure the accuracy of microseismic station location.