The microtexture of AZ31 magnesium alloy with compression deformation was studied by electron backscatter diffraction (EBSD) in situ tracking. The microtexture evolvement of the same observation areas of the alloy sheets which were compressed three times continually (deformation of 11%, 17% and 23%, respectively) were investigated. The results show that the microtexture of as-rolled AZ31 magnesium alloy is typical (0001) basic texture. With deformation of 11% and the temperature of 170 oC, the grain orientation changes remarkably, most grains have been twined fully and a few grains twined partially. The initial basic rolled texture is weakened a lot, and twined grains tropism accord with 60°/ and 86.3°/ orientation. With the increasing of deformation, sliding is start-up, twined boundary decreases and variation of microtexture is not obvious. In compression deformation of AZ31 magnesium alloy, the evolution mechanism of microtexture is the tension twinning, without compression twinning.