Zinc oxide (ZnO) as a kind of common electron transport layer material is widely used in transparent electronics. InGaAs which is a GaAs compound material, has higher mobility and a wider bandgap than silicon (Si). So, in this paper, we propose ZnO/InGaAs solar cells, in addition, three methods are given to enhance the performances. The first and most effective way is to reduce conduction band offset of ZnO/InGaAs solar cells by doping Mg and altering mole fraction of indium to maximize the amplitude of power conversion efficiency (PCE) to more than 10%. The PCE is no longer increasing obviously below zero conduction band offset. The second one is to increase the ZnO carrier concentration to maximize the amplitude of PCE to more than 5%. And the last one is to reduce the interface defect density between the two materials, which is more suitable for large conduction band offset. The maximum PCE of the ZnO/InGaAs solar cells in this paper could be up to 24.26%.