Effects of Sn addition on the microstructure corrosion rate and electrochemical properties of AZ61 magnesium anodes in 3.5% NaCl solution were studied. The results showed that with the addition of tinβphase was restrained and a new second phase was observed which increased with the content of tin increasing. the activity and electrochemical properties of Mg alloys were improved due to the addition of tin. With increase of tin the corrosion rate increased slightly and both of the self-corrosion potential and discharge potential shifted negatively. The electrochemical properties of magnesium abodes with 3% tin were better than AP65.