The invention provides a micro-earthquake focus rapid positioning method based on an arrival time difference database, and belongs to the earthquake focus positioning technology field. The micro-earthquake focus rapid positioning method comprises the steps that a geological numerical model of a monitoring area is established, and mesh division is carried out, and every mesh point is adopted as a characteristic earthquake focus point; by combining with the characteristic earthquake focus point, a sensor position coordinate, and an earthquake focus wave speed, a characteristic earthquake focus point arrival time difference database is established; by using a waveform information acquisition system, the time of the earthquake source waves arriving at different sensors is extracted from waveform signals received from the sensors; the arrival time difference between any two sensors is calculated, and the arrival time difference matrix of the earthquake focus is established, and the matching searching of the arrival time difference matrix and the characteristic earthquake focus point arrival time difference database is carried out to realize the real-time rapid positioning of the earthquake focus. During an actual micro-earthquake monitoring project, the characteristic earthquake focus point arrival time difference database is established in advance, and the function optimization iteration solution of the earthquake focus is not required, and therefore time required by the earthquake focus positioning is greatly reduced, and rock mass engineering dynamic disaster early warning time is effectively reduced.