Mg-3wt.%Y alloys were processed by cyclic extrusion and compression (CEC) up to 7 passes at different temperatures from 375 to 450 °C, respectively. The microstructure was effectively refined and the mean grain size was decreased from 800 μm to 3–15 μm. Tensile and compressive tests were performed at room temperature at an initial strain rate of 1.11 × 10-3 s-1. The experimental results show that after 7-pass CEC processing the tensile yield strength and elongation-to-failure of Mg-3Y alloy increased simultaneously. Furthermore, the strength differential effect (SDE) of tension-compression of the alloy was weakened, especially the SDE value was only 3.3% when processed at 400 °C.