A strong basal plane texture of AZ31 magnesium alloy was obtained by severe hot-rolling with three passes falling temperature. The effects of annealing time and annealing temperature on the evolution of texture at different layers were studied by means of X-ray texture analysis. The results showed that the orientation density of basal plane texture component was reduced greatly tending to dispersion with increasing annealing time and temperature. The hard orientation can be greatly weakened by softening annealing, the best basal plane orientation was obtained when the annealing time is 60min and the annealing temperature is 150~300°C. A texture gradient along thickness direction with annealing has been found in the sheet. The texture gradient was the lowest when the annealing time is 60min and the annealing temperature is 300°C.