Abstract：Taking the electroforming of Ni-Co alloy as an example, the area effects were studied by analyzing the correlations between the area ratio of Ni-Co combined anodes and the compositions of the alloy deposits as well as by measuring of the polarization curves when the Ni-Co combined anodes were used. Experimental results showed that, when the same current was applied to each single anode, the composition of the Ni-Co alloy deposits varied dramatically with the ratio of the anode areas in a nonproportional manner; with the same anode area ratio, the composition of the electroformed alloy deposits hardly changed with the applied current of each anode; when the Ni-Co anode area ratio was 1∶ 1 or 3∶ 1, the composition of the corresponding Ni-Co deposits was maintained within a narrow range, the content of Co being 27. 1% ～ 28. 2% and 22. 3% ～ 24. 5%, respectively; the microhardness of the Ni-Co alloys was greatly affected by the ratio of anode area, and increased with the increase of Co content. In the case of electroforming using single-metal soluble combined anodes, the composition of the alloy deposits was mainly determined by the area ratio of the anodes, and by the area ratio of the anode to the cathode, but not by the current applied to each anode.