The invention provides a large-diameter high-strength bolt connection pair torque coefficient measuring device. The device comprises a torque measuring device fixed at the head of a bolt connection pair to be measured, a ratchet wrench fixed at the tail of the bolt connection pair to be measured, a shaft force sensor arranged on the bolt connection pair to be measured in a sleeving manner and a thread limiting block; the head of the bolt connection pair to be measured is connected with the torque measuring device through a first sleeve, the tail of the bolt connection pair to be measured is connected with the ratchet wrench through a torque multiplier, and the torque multiplier is connected with the tail of the bolt connection pair to be measured through a second sleeve matched with the torque multiplier; and a screw rod of the bolt connection pair to be measured penetrates through an axial force sensor, penetrates the thread limiting block and is fixed through a matched nut. The large-diameter high-strength bolt connection pair torque coefficient measuring device is high in detection precision, good in reliability, relatively low in cost and simple in structure; the torque multiplier can provide larger screwing torque with smaller force, so that the large-diameter high-strength bolt connection pair torque coefficient measuring device is easy for a single person to operate; andthe application range is wide, and the large-diameter high-strength bolt connection pair torque coefficient measuring device can be adjusted according to different bolt specifications and torque ranges.