An automatic attaching 3D tempered glass screen protector attaching machine, comprising an identification device, wherein the identification device comprises: a processor, a camera and a memory; the camera is configured to collect a front picture and a back picture of the mobile phone; the processor is configured to identify the back picture to determine the brand of the mobile phone, and identify the front picture to determine the model of the mobile phone; and further determine the category of the screen protector according to the brand and model of the mobile phone, and send the category to the attaching mechanism to complete attaching the screen protector.