Modular assembling structure for extension card

The utility model discloses an expansion board module assembly structure, which comprises a positioning frame. The positioning frame is made of the back window of the shell bent upward, and the opening is directed at the main board. The positioning frame is arranged on a fixing frame, whose one end is arranged with a support, on the side plate of which is a transfer card. In actual assembly, users push an expansion card into the bracket and insert it into the slot of the transfer card, and the lock the expansion card on the fixing frame. Then, users place the expansion card module on the positioning frame, insert the transfer card into the corresponding expansion groove on the main board, and lock the fixing frame on the positioning frame, thus assembling the expansion card module on the back window base.