Amorphous MgNi hydrogen storage alloy was synthesized by mechanically alloying (MA). The electrochemistry property of the alloy prepared in different parameters was tested. The relationship between the mechanically alloying parameters, the microstructure of the alloy and the electrochemistry property was analyzed. The results show that the eclectrochemistry property of the alloy has a strong relationship with milling speed, ball/powder weight ration(R) and milling time.