The purpose of this paper is to explore the effects of equal-channel angular pressed (ECAP) process on the microstructure and corrosion behavior of biomedical Mg-Zn-Ca Alloy. As-cast Mg-3Zn-0.2Ca alloy was extruded for 1-4 passes by ECAP using route A process. The influences of ECAP process on the microstructure, texture and corrosion behavior of Mg-3Zn-0.2Ca alloy were investigated by optical microstructure observation, X-ray reflection and electrochemical methods. Particularly, the effects of ECAP process on the microstructure evolution and electrochemical corrosion behavior in simulated body fluid on the different cross-section of ECAPed alloy. The results indicated that with increasing ECAP passes, grain size of Mg-3Zn-0.2Ca alloy gradually refined, and (0002) basal texture emerged after ECAP 4 passes. With increasing ECAP passes, the corrosion resistance of Mg-3Zn-0.2Ca alloy increased firstly and then decreased. The influence of ECAP process on corrosion resistance of Mg-3Zn-0.2Ca was the combined action of grain size, crystal defect and texture. The corrosion resistance of ED, TD and ND cross-section of ECAPed alloy were different, and the corrosion resistance of TD section is superior to the other two directions.