The invention relates to a P and S wave combined quick positioning method and system for microseism in a well, and the method comprises the steps: a, obtaining the microseism data of the same event, carrying out the vector decomposition of the microseism data of the same event, and obtaining two vertical azimuth angles of a three-component detector; b, building the function relation, which takes the three-component detector as the start point, between a vertical depth H and a horizontal distance L according to the snell law; c, building a P&S wave depth target function related with the position of a seismic focus, enabling the target function to be minimized through depth scanning, calculating the vertical depth and horizontal distance of the seismic focus relative to the three-component detector, and achieving the P and S wave combined quick positioning. The method just employs two vertical azimuth angles of the three-component detector, builds the P&S wave depth target function related with the position of the seismic focus according to the snell law, enables the target function to be minimized through depth scanning, and can achieve the P and S wave combined quick positioning.