To investigate the influence of longitudinal wave rolling (LR) on the microscopic orientation of AZ31B magnesium alloy, this paper studied the heat treatment of AZ31B magnesium alloy sheet at 400 ℃/20 min and 450℃/20 min. Wave-flat and flat-flat rolling was carried out in wave-flat and flat-flat rolling, the amplitude of the corrugated roll is 4mm and the period is 0.35mm. The grain size and orientation at wave trough, wave waist and wave peak were analyzed by EBSD. The results show that both the basal texture strength and average grain size decrease after heat treatment, and the basal texture strength decreases significantly after heat treatment at 450℃/20min, but the average grain size increases. After 400℃/20min+LR, the average grain size of the plate decreases significantly, the basal texture strength at wave peaks and troughs increases compared with that at heat treated samples, and the basal texture strength of the wave lumbar is almost unchanged. However, due to the deflection of a large number of grains at wave peaks and troughs along the opposite direction of RD, the overall macro-texture strength decreases significantly. After the second pass, the surface basal texture strength at the peak and trough of 400℃/20min+LFR is significantly lower than that at the corresponding position after 400℃/20min+LR, while the wave waist strength is significantly enhanced, and the average grain size is further reduced. Compared with 400℃/20min+FFR, the texture strength of base plane is weaker than that of wave waist but stronger than that of wave peak and trough. Therefore, the overall base texture strength of LFR and FFR plates is close to each other at 400℃. The substrate texture strength of the plate after 450℃/20min+FFR is significantly lower than that after 400℃/20min+FFR, and the texture proportion of {0001}<11-20> type is lower, the average grain size increases.