The utility model discloses a transmission gear box structure which is suitable for a plurality of industries such as metallurgy, petroleum, chemical engineering, sugaring, mine, transportation and the like. The structure mainly comprises a gear box body, a box cover, a bevel gear transmission mechanism and a first planetary gear transmission mechanism, wherein a first sun wheel shaft of the first planetary gear transmission mechanism is skillfully designed to be in a flexible long shaft structure; a first planetary carrier and a hollow gear shaft are movably sleeved on the first sun wheel shaft; and input power is transferred to an output stage gear by the first planetary gear transmission mechanism and the hollow gear shaft through the bevel gear transmission mechanism, then is output at a plurality of angles by an output shaft. The improved structure is more compact, and has the advantages of small size, light weight, high overall gear ratio, strong output torque, high bearing capacity, stability in transmission, high transmission efficiency and the like; and a power transfer structure can be adjusted according to different use locations, so that special mounting requirements of whole equipment are satisfied, the equipment purchasing cost is reduced, the industrial application range is widened, and the economic advantage is improved.