A planner heterojunction quantum dot solar cells (QDSCs) structure of FTO/TiO2/PbS-EMII/PbS-EDT/Au is fabricated via layer-by-layer spin coating method, and then the temperature dependent photovoltaic performance of QDSCs is studied. The results indicate that the environment temperature has great influence on the current density-voltage (J-V) characteristics of quantum dot solar cell. The short-circuit photocurrent density (J(SC)), open-circuit voltage (V-OC) and fill factor (FF) are all increased when the temperature decreases from 353 K to 253 K. A top value of power conversation efficiency (PCE, 9.78%) is obtained for the QDSCs when the environment temperature is lowered to 253 K, with a V-OC of 0.63 V, J(SC) of 33.1 mA/cm(2) and FF of 0.47, which is 33% above the PCE at room temperature (7.34%). In conclusion, it is necessary to cool the device for keeping the high efficiency operation of solar cell.