The Cu(In,Ga)Se2(CIGS) film was deposited on Mo-coated sodalime glass by three stage co-evaporation of elemental In, Ga, Cu, and Se sources. The Se flux during the co-evaporation has great influence on the microstructure of CIGS layer. The surface region of CIGS film showed pores when the Se flux was large. The conversion efficiency of CdS/CIGS solar cells was depended on the CIGS surface morphology. The best CIGS solar cell was obtained at 15 A/s Se vapor pressure condition and it had the following photovoltaic parameters: conversion efficiency of 17.57%, Jsc = 36.48 mA/cm2, Voc = 0.655 V and FF = 73.5% in an active area of 0.421 cm2.