Abstract： A proper cycle counting method should be selected when predicting the fatigue life of engineering components under variableamplitude and multiaxial random loading. Based on the critical plane method, the Langlais multiaxial rainflow counting algorithm was discussed. Then, a modified Langlais multiaxial rainflow algorithm was proposed and a realization method for modified Langlais multiaxial rainflow algorithm was developed. The modified Langlais multiaxial rainflow algorithm can accurately take into account all load information in the auxiliary channel, corresponding to a complete cycle in the counting channel. And it can be used for the enclosing surface method to calculate the effective stress or strain range. For a new cycle counting process of the 3point rainflow method, the method of choosing the starting point was modified, which improved the efficiency of cycle counting.