In order to obtain the changing law of the fatigue reliability of cement concrete for the highway pavement under high stress ratios, firstly the probability densities of monotonic random variables including cement concrete fatigue life were deduced. And then the fatigue damage probability densities of the Miner, Chaboche Zhao and modified Chaboche Zhao models were deduced.By virtue of the fatigue test results, fatigue damage probability density functions of the three models were obtained. Finally, substituting load cycles into the functions the changing law of cement concrete fatigue reliability with load cycle was acquired.The results show that under the same stress ratio， with the increase in the load cycle the fatigue reliability declines from almost 100% to 0% gradually.Under any stress ratio, in the initial stage of load action, there is always a relatively stable phase for fatigue reliability.With the increase in the stress ratio, the phase diminishes gradually and the load cycle corresponding to reliability of 0% also decreases. In descent phase of reliability， the higher stress ratio is, the lower concrete reliability is for the same load cycle. Besides, relative to the modified Chaboche Zhao fatigue damage model, the Miner fatigue damage model is safer.