The invention discloses a nut locking device and a combined roller with the same. The nut locking device is characterized by comprising a reactive force supporting plate which fixedly sleeves a firstend of a shaft, a locking nut which tightly sleeves a second end of the shaft, and an accessory which fixedly sleeves the middle part of the shaft; and a first end surface of the accessory is fixedlyconnected with the end surface, close to the reactive force supporting plate, of the shaft, a second end surface of the accessory is fixedly connected with the first end surface of the locking nut, and a hydraulic driving part used for driving the locking nut to lock the accessory is arranged outside the locking nut. According to the nut locking device and the combined roller with the same, the combined connection strength is high, assembly pressure is stable, and assembly and disassembly are convenient.