The preparation technology of electrodeposited Mg-Ni hydrogen absorbing alloy was studied by using orthogonal tests in this paper. The results show that according to the purpose of higher special discharge capacity, the descending order of the influencing factors is temperature, content of MgCl2 , content of NaH2PO2 , current density and content of C6H5Na3O7. The discharge capacity of the alloy reaches 250 mAh/g under the depositing conditions of current density 100 mA/cm2, temperature 45 ℃, content of MgCl2 180 g/L, NaH2PO2·H2O 70 g/L , C6H5Na3O7·H2O 60 g/L , NiCl2 30 g/L, H3BO3 30 g/L and pH 3 ~ 4. It has obvious charge-discharge platforms and its capacity reaches the maximum in the first charge-discharge cycle but falls fast with the increase of cycles. The result of XRD shows that the alloy is composed of amorphous Mg2Ni + Ni phases.