In order to investigate the effect of Nd on the microstructure and corrosion resistance of Mg-Zn-Mn-Ca alloy, 0.4 wt% Nd was added into Mg-6Zn-1Mn-0.5Ca alloy. OM, SEM equipped with EDS and XRD were used to characterize the microstructures, and crystal structures. The bio-corrosion resistance were studied by immersion corrosion, hydrogen evolution and electrochemical measurement in simulated body fluid (SBF). Results show that the grain size decreases with the addition of Nd. A mixture of secondary phases Ca2Mg6Zn3+Mg41Nd5 is found in Mg-6Zn-1Mn-0.5Ca-0.4Nd alloy. After immersion in SBF for 7 d, more such mixture still remains on the Nd-containing alloy surface, whereas few Ca2Mg6Zn3 particles remain on the alloy without Nd. Thus, the bio-corrosion resistance increases due to presence of Nd.