The invention discloses a belt winding device and a belt winding method. A rack is included and is provided with a driving motor and a reel device, two reversing transmission drums are arranged at theother end of the rack, the lower part of the rack is provided with a transmission drum, and a platform on the upper part of the rack is provided with an adjustable belt pressing support and a cuttingblade; the rack is provided with a limiting carrier roller; the reel device comprises two fixing discs and three roller columns detachably arranged between the two fixing discs; fixing plates are fixedly arranged at the both ends of the roller columns, and the fixing plates and the fixing discs are fixed through bolts; the reel device is connected to the rack through the fixing disc at one end and is connected with the driving motor through the fixing disc at the other end; and the driving motor is provided with a speed reducer. The device has large belt winding force, is controllable in speed, saves time and labor, greatly improves the labor efficiency of belt winding work, and reduces labor intensity of workers.