An earthquake early warning method for an earthquake detecting system includes utilizing support vector regression (SVR) method to build an earthquake detecting model according to the a plurality of vectors, wherein each of the vectors is corresponding to an earthquake information and a ground motion intensity; detecting a new earthquake information of a new earthquake and generating a specific vector according to the new earthquake information when the new earthquake occurs; and predicting a new ground motion intensity of the new earthquake according to the specific vector and the earthquake detecting model.