Polycrystalline Cu(In,Ga)Se2 (CIGS) thin ?lms are deposited onto soda-lime glass substrates by the low-temperature three-stage process (below substrate temperature of 420℃). The influences of growth rate in the second stage on structural and electrical properties of CIGS thin film and device performance are investigated. With the increase of deposition rate during the second stage, the crystallinity and grain compactness of CIGS thin film are promoted, and the double-peak reflection pattern is reduced obviously,which can reduce the recombination in the grain boundary and help to improve the conversion efficiency of the CIGS solar cell significantly. However, according to the experimental results, higher growth rate during the second stage leads to rough surface and low carrier concentration. The larger surface roughness can be attributed to the larger grain size of secondary-phase Cu2-xSe, and the lower carrier concentration results from the reduction of passivation donor defect effect which is induced by the hindrance of Na diffusion from the glass substrate. High growth rate in the second stage is found to be able to increase the interface recombination and induce shunt paths in the solar cell and then the open circuit voltage and the cell parameters are deteriorated. Finally, a high conversion efficiency of 11.24% is achieved by optimizing the growth rate in the second stage.