A keyboard structure and assembling method thereof are provided. The keyboard structure includes a baseplate, a keycap and a frame having a hook body. The keycap can be inserted into the frame and restricted by the hook body, so that the range of movement of the keycap is restricted. The keycap cannot be separated from the frame so that the coupling of the frame and the baseplate is not interfered by the keycap. Thus, the present invention can effectively simplify the assembling process of the keyboard.