The invention discloses a weighing and pressurizing device arranged on an on-line friction belt conveyor. According to a method, two sets of weighing devices and a set of pressurizing device are included, and the pressurizing device is fixed between the two sets of weighing devices; each weighing device comprises a conveying belt, carrier rollers and the like, wherein the carrier rollers are arranged below the conveying belt, a bearing plate is arranged below the carrier rollers, and weighing sensors are arranged below the bearing plate; and the pressurizing device is composed of an upper cross beam and two end structures, the upper cross beam is arranged above the conveying belts, the two end structures are the same and are symmetrically arranged,each end structure is composed of a supporting frame, an upper gear and the like, each supporting frame is provided with horizontal holes and inclined holes, the upper cross beam penetrates through the horizontal holes, the upper gears penetrate through the upper cross beam, one end of a long round pipe penetrates through the inclined holes, the other end of the long round pipe is in contact with the side edges of the conveying belts, a sleeve penetrates through the long round pipe, lower gears are meshed with the upper gears, a spring sleeves the long round pipe, one end of the spring makes contact with the sleeve, and the other endof the spring makes contact with with a protruding baffle of the long round pipe. The tension of the conveying belts can be controlled, the cost is low, and maintenance is convenient.