Abstract: A clamp fixing structure for connecting circuit boards. The structure includes an inlet slot terminal on each end of a connecting socket and a fixing set to be assembled with each terminal. Below and adjacent to the terminal are a catch slot and fixing holes, and a vertical slide guide is on one side of the terminal. On the fixing set, at corresponding mating positions of the catch slot, fixing holes, and slide guide of the terminal are respectively hook, inserting pins, and a slide to firmly fix a metal clamp when the fixing set is assembled with the inlet slot terminal.