The invention discloses a warning function torque spanner provided with a transparent pressing cover plate. The warning function torque spanner comprises a spanner body. One end of the spanner is a double offset ring spanner head which comprises a mounting hole and an accommodation cavity. The mounting hole is internally provided with a torque ring. The lower portion of the torque ring is provided with a jacking block which is arranged on one side of the accommodation cavity, and the other side of the accommodation cavity is provided with a spring. One end of the spring abuts against the jacking block, and the other end of the spring abuts against the inner wall face of the accommodation cavity. An indication arrow is arranged on the position, where the rear end portion of the jacking block intersects with the torque ring, of the torque ring. The pressing cover plate is arranged outside the double offset ring spanner head, connected with the double offset ring spanner head through screws and made from a transparent material. The warning function torque spanner is simple in structure, can achieve a warning function and is convenient to use and low in cost; and the warning function torque spanner is internally provided with gear points, part overloading is effectively prevented, and spring failure caused by excessive spring compression is avoided.