Cu(II)Cu(I)/activated carbon (AC) catalysts with different copper chloride and cuprous chloride impregnation orders were prepared. The effect of the Cu(II) additive on the catalytic performance of Cu(I)/AC catalysts for gas-solid acetylene dimerization was evaluated. The optimal catalytic performance was obtained using the Cu(II)0.3Cu(I)1/AC catalyst with an average acetylene conversion of 70.0%. This value was an increase of 33.0% compared to the average acetylene conversion of 37.0% (Cu(I)1/AC) under the same reaction conditions. The results from the characterization of the Cu(II)Cu(I)/AC catalysts demonstrated that the addition of Cu(II) increased the dispersion of copper and inhibited copper loss on the catalysts. Consequently, our findings indicate that a suitable Cu+/Cu2+ molar ratio improves the catalytic performance and stability.