The structure of the magnesium alloy Mg-1%Zn-0.2%Ca after equal-channel angular pressing (ECAP) has been studied by optical and scanning electron microscopy. It was established that increasing the equivalent strain by increase a number of passes through a ECAP die leads to more pronounced grain refinement in the alloy. When equivalent strain achieved 7.2, an average grain size of 2 μm was observed. It was shown that the ECAP samples enable to demonstrate the high microhardness of 69.5 HV and the enhanced ultimate tensile strength of 282 MPa, which is more than 2 times higher in comparison with the homogenized state, while maintaining ductility.