Massive malicious jamming devices and advanced jamming techniques have been emerged along with the development of wireless communication networks. In order to effectively eliminate the harmful interference, a new scheme known as the cognitive frequency hopping (CHF) is proposed recently, which can evaluate the occupancy of frequency hopping slots and adjust the parameters dynamically according to the spectrum sensing results. Although the existing literature only shows that CFH systems can achieve reliable data transmission, the factors affecting the reliability are rarely analyzed. Therefore, we analyze the reliability performance of the CHF systems in this article, and define a new metric named anti-interference tolerance to measure the reliability performance of the CHF systems. Moreover, we derive the analytic expression of anti-interference tolerance by analyzing the effect of false alarm probability, missed detection probability, and communication link convergence delay. Simulation results validate the effectiveness of our analyses for measuring the reliability capacity of the CHF systems. To satisfy the demands of different communication scenarios, the CFH systems can adjust relevant parameters in the light of our theoretical derivation.