A computer automatic assembly system is proposed. The computer automatic assembly system includes: a database for storing information of an assembly and mounting area of a part combined to a mainboard, and program information such as information of a BIOS, a driving driver, and an operating system, and periodically updating the corresponding information through a communication part including a wired/wireless communication network; a device digestive module for checking the part through a photographing means, moving the checked part to the assembly and mounting area of the part provided on the mainboard through the photographing means and a robot arm for transfer, assembling, and mounting the part, and then writing a driving program and circuit information of the part; and an administrator terminal for periodically upgrading or updating part information necessary for the device digestive module by a part company server through a communication network including the wired/wireless communication network.