The effects of Si content on the electrochemical performance of Al-5Zn-0.03In-1Mg- 0.05Ti (wt.%) alloy were studied by the electrochemical measurements and metallographic method. The optimal microstructures and electrochemical performance were obtained when the Si content in Al-Zn-In-Mg-Ti alloy was 0.1 wt.%. This anode alloy shows a current efficiency of 94.3% with even corrosion. However, in the case of Si content over 0.1 wt.%, the electrochemical performance of aluminum sacrificial anode shows only a nil improvement, and the corrosion morphology becomes uneven. The results reveal that the appropriate amount of Si is effective on reducing the harmful effect of iron impurities, improving the non-uniform corrosion and the electrochemistry performance of Al-Zn-In-Mg-Ti alloy.