A removal mechanism of the daughter board includes a fixed frame, a moving frame, a moved frame and a handle. The fixed frame has a pushed portion. The moving frame is movably coupled to the fixed frame and has an oblique tapered edge. The moved frame is fixed to the daughter board and has a corresponding oblique edge. The handle is rotatably connected to the moving frame and has a pushing portion, and the pushed portion is on a rotation path that the pushing portion rotates with the handle. When the handle is operated, the pushing portion pushes the pushed portion, the moving frame moves relative to the fixed frame to push the corresponding oblique edge by the oblique tapered edge. The moved frame drives the daughter board to be removed from the connector.