CdS/CdSe system of quantum dot co-sensitized solar cell is one of the most attractive structures for highefficiency due to its effect of adjusting level.However,the stepped structure formed between levels of CdS and CdSe has a limitation which offering a chance for efficiencies enhanced.Metal ion doping in quantum dots has emerged as a common way for changing the Fermi level,bandgap and conductance.Here we report the Mn doping of CdS in the CdS/CdSe quantum dot co-sensitized solar cells on conditions of different doping concentration and number of CdS SILAR.