The invention discloses a method for evaluating the difference in gas injection effect of gas injection wells in a carbonate reservoir, aiming at solving the problem that the difference in effect characters of gas injection wells cannot be systematically evaluated in the prior art, and realizing the purposes of systematically and completely evaluating the difference in gas injection effect in the carbonate reservoir and finding out the reason of low efficiency. By means of the invention, reasons for low gas injection efficiency corresponding to different geological classifications are obtained, systematic classification and induction are carried out on the difference in gas injection effect, and gas injection effects are effectively evaluated, so that a sufficient gas injection scheme design basis is provided for subsequent development and production increase, and a significant guiding principle is provided for later-stage gas injection and production increase of the carbonate reservoir.