A motor for a treadmill, containing at least a housing (1), a stator (2), a rotor (3) having a rotating shaft (4), a front end cover (9), a rear end cover (5), and a flywheel (13). The front end cover (9) and the rear end cover (5) are disposed on both ends of the housing (1), respectively. The stator (2) and the rotor (3) are disposed in the housing (1). A front end of the rotating shaft (4) extends from the housing (1). The flywheel (13) is disposed on the front end of the rotating shaft (4). The rotating shaft (4) is connected to the flywheel (13) via key (14). A sleeve (12) is fit on the front end of the rotating shaft (4). The sleeve (12) abuts against the flywheel (13). A locking device is disposed at the end of the rotating shaft (4) and tightly fixes the flywheel (13).