A projection image automatic correction method and system based on binocular vision. The method includes: acquiring a depth map of a projection image on a projection plane; calculating a first transformation relationship between a source image and the projection image; acquiring a distortion image according to the depth map; acquiring a correction image after correcting the distortion image; calculating a second transformation relationship between the distortion image and the correction image; acquiring a correction relationship between the source image and the correction image according to the first transformation relationship and the second transformation relationship; and correcting the projection image according to the correction relationship. This disclosure is configured to realize the efficient automatic correction of the projection image without being limited by the projection area, and the correction flexibility is high.