The invention discloses a bolt tensioner capable of realizing long-distance transmission. The bolt tensioner comprises a motor, a speed reducer, a rear-end transmission joint, a plurality of middle transmission joints, a front-end transmission joint and a bolt assembling and disassembling machine mounting base; the speed reducer, the rear-end transmission joint, the plurality of the middle transmission joints and the front-end transmission joint are sequentially transmitted through the motor; the front-end transmission joint drives the bolt assembling and disassembling machine mounting base and a bolt assembling and disassembling machine to realize operation in a narrow bent space; joints among the rear-end transmission joint, the plurality of the middle transmission joints and the front-end transmission joint are further connected to connecting sleeves through gears; connected ends of the connecting sleeves can rotate around rotary shafts, so that a bolt assembling and disassembling device is bent; and the rear-end transmission joint, the plurality of the middle transmission joints and the front-end transmission joint are in transmission through a plurality of chains, and the rotary shafts driven by the chains can rotate in limiting slots of the sleeves, so that the bolt assembling and disassembling device can be steered and bent.