Disclosed is a spanner tool for mounting or dismounting components, which comprises a control piece (2), a connecting piece (1) and a rotating piece (3). The connecting piece (1) is hinged with one end of the control piece (2) and one end of the rotating piece (3) respectively. An angle β formed between the control piece (2) and the connecting piece (1) is less than an angle α formed between the rotating piece (3) and the connecting piece (1) when the control piece (2) and the rotating piece (3) respectively rotate to limit positions at different sides of the connecting piece (1). The spanner tool is practical and reliable. The spanner tool is convenient and rapid-in-use. The spanner tool can be folded for portability when not in use. Additionally, locking tightness of the tool can be adjusted by adjusting a nut.