AZ31 magnesium alloy sheets were processed by normal rolling (NR), one-pass equal channel angular rolling (1P-ECAR), and cross equal channel angular rolling (C-ECAR) at 400 degrees C on a die with 105 degrees channel angle. The microstructure, texture, and tensile properties of sheets were measured. The results show that ECAR processing can weaken the basal plane texture, thus obviously improve the mechanical properties. The yield ratio sigma(s)/sigma(b) decreases and strain hardening exponent n increases along rolling direction (RD) during ECAR, which means that the uniform plastic formability is enhanced. After C-ECAR, the mechanical properties along both the RD and transverse direction (TD) are improved. Different twinning types, fine {10 (1) over bar1} contraction twinning in the NRed sheets and coarse {10 (1) over bar2} extension twinning in the ECARed sheets, were observed. The easier activation of {10 (1) over bar2} twinning and basal < a > slip leads to the lower yield strength of the ECARed sheets. Dynamic recrystallization (DRX) during the rolling process has great effect on the microstructure of the as-deformed and annealed sheets. The annealed C-ECARed sheets have significant finer and homogenous grains than the annealed NRed sheets, which is attributed to the rarely DRX process during ECAR. The average grain sizes of the annealed C-ECARed samples and NRed samples are 14 and 24 mu m, respectively.