Mg-6Zn-0.6Zr magnesium alloy (ZK60) was extruded by equal channel angular processing (ECAP) equipment via 2, 4, 6 passes at 400°C. The corresponding microstructure and hardness were examined. The change of the crystal plane in this processing was analyzed by X-ray diffraction. The results show that, ECAP favors recrystallization and refines grains with the increase of pass times. The grains are significantly refined to 10um after 6 passes and the hardness is improved to 79.8HV after 4 passes.