The invention relates to a composite insulator fitting and core rod assembling process. A groove matched and connected with the core rod is formed in the end part of the fitting; the assembling process comprises the following steps of (1) coating the inner wall of the groove in the end part of the fitting with a layer of adhesive with thickness of 0.04-2mm, wherein the adhesive is prepared from 595 curing agent and epoxy resin E54 at the mass ratio of 2-5 to 100; (2) assembling the two ends of the core rod to the groove in the end part of the fitting to enable the core rod to be in contact with the adhesive in the groove for 20-30s, next, rotating the core rod for 180 degrees and next, continuously curing for 20-30s; and (3) applying pressure to the fitting from the outer side to the inner side in sequence by tightening a die, wherein the crimping and pressure-maintaining time is 3-5s to enable the fitting to be deformed so as to hold the core rod tightly. The advantages as follows can be achieved: by virtue of the assembling process, the connection firmness between the core rod and the fitting can be effectively improved, so that potential safety hazard in use can be further eliminated.