Abstract: A mouse with a plurality of buttons has a PS/2 driver as interface connected to a computer. A 4-bytes packet generated by the mouse is provided for the computer to analyze so as to update the display state of the mouse in the display and to perform specified function. This 4-bytes packet also has the 4th byte for controlling the movement of the mouse in vertical or horizontal scrolling direction and expanding the functions of the mouse. Therefore, it may not only greatly improve the convenience of control between the mouse and the computer, but also, comparing with the prior mouse, improve the expandability of many functions.