Abstract: Bidirectional cyclic bending technology(BCBT) had been used to improve the microstructure and texture and mechanical properties of AZ31 magnesium alloy sheet. When AZ31 Magnesium alloy sheet deformec by BCBT, the recrystallization had occurred in twins boundary, and across area between twins boundary and crystal boundary, and across area between twins and twins. And grain size was less than twins width. When deformation temperature of BCBT was 523K, the recrystallization nucleation had occurred in crystal boundary and grown up quickly. When deformation temperature was 483K and deformation process was 3 times, basal texture of AZ31 magnesium alloy sheet was weakened, and texture intensity was reduced from 9.59 to 3.54, and average grain size was 12.2μm，and elongation ratio was 17.1% at room temperature. .