The invention discloses a method for detecting defects of a screen printing area of a smart phone glass cover plate based on machine vision. The method comprises the following steps of: collecting animage of a mobile phone screen; reading related parameter information; detecting a window; performing major defect extraction on the outline of the screen printing area of the mobile phone cover plate, dividing a detection area into the screen printing area, a hole and character area, a light band area and an interference area; obtaining the defects of each area; correcting the outline of the mobile phone cover plate to obtain the defect information of edge breakage; performing dotted, linear, and planar defect classification by using a neural network classifier; screening the defects according to the standard of defect definition; performing deep defect classification on the linear defects, IR hole defects, and character defects by using deep learning, wherein the linear defects comprisebroken filaments, scratches, IR hole defects, and the like; and counting the form information of various defects. The method can realize the universal application of various models, performs on-line adjustment according to different detection standards, and can quickly and accurately extracts defects such as pocking marks, broken filaments, scratches and dirt.