A main cable anchoring device of a gantry crane comprises a cable casing pipe, a cable fixing clip, a bottom beam steel channel, a rotary shaft, locating pipes and rotary shaft sleeves. The cable casing pipe is formed by combining two semicircular iron pipes and is arranged on a main cable in a sleeving manner. The cable fixing clip can be opened, and a half side of the cable fixing clip and the cable casing pipe are integrated. One end of the bottom beam steel channel is fixed to a steel rail through a steel rail pressing plate and bolts, and the other end of the bottom beam steel channel is connected with two pieces of angle iron through bolts. The rotary shaft is arranged between the two pieces of angle iron in a penetrating manner. The locating pipes are arranged at the two ends of the rotary shaft in a sleeving manner, and located between the two pieces of angle irons. One end of each rotary shaft sleeve is arranged in the middle of the rotary shaft in a sleeving manner, and the other ends of the rotary shaft sleeves are welded to the bottom of the cable casing pipe. The main cable anchoring device is simple in structure, easy to machine and manufacture, low in cost, convenient to dismount and capable of being used repeatedly, and the problems that the cable is likely to loosen and irregular in winding, and consumes time and labor when mounted, and is likely to be damaged are effectively solved. The main cable anchoring device has high practical application value and promotional value.