The invention provides a steam generator heat transfer tube detection equipment positioning and connecting mechanism which comprises a rotary cylinder, an end cover, an inner cylinder barrel, a coupler, a torsion spring, a transmission shaft, an outer cylinder barrel, a special-shaped shaft, an expansion tube and an air port. The special-shaped shaft is arranged in the expansion tube, the rotary cylinder is mounted on the end cover and then mounted on the inner cylinder barrel through the end cover, an output shaft of the rotary cylinder is connected with the transmission shaft through the coupler, the torsion spring is mounted on the transmission shaft, one end of the torsion spring is fixed onto the inner cylinder barrel, the other end of the torsion spring is fixed onto the transmission shaft, a plurality of projections are arranged at one section of a shaft body of the special-shaped shaft, one end of the special-shaped shaft is connected with the transmission shaft, one end of the expansion tube is provided with a plurality of axial narrow grooves, a plurality of grooves are formed in the section of the expansion tube and matched with the projections on the special-shaped shaft, and the other end of the expansion tube is connected with the inner cylinder barrel. The positioning and connecting mechanism solves the technical problems of jamming and unstable and unreliable running in the prior art.