The invention provides a microseism focus positioning method based on a double-difference method, and belongs to the field of geophysical prospecting of petroleum. The microseism focus positioning method selects a perforation event as the main event, and picks the observation travel time for a microseism event, and can determine the relative distance between the perforation and the microseism event by calculating the residual error (double difference) between the observation travel time of the perforation and the microseism event and the theoretically calculated travel time difference. The microseism focus positioning method based on a double-difference method is high in operation speed and efficiency, and is easy for local convergence. As the microseism focus positioning method based on a double-difference method has the relative main event, the relative positioning accuracy is higher and the microseism focus positioning method is not limited by the spacial scale. The microseism focus positioning method based on a double-difference method offsets the error caused by changes of the speed of the near surface and the stratum speed, and can improve the positioning accuracy.