Abstract: The Cu-In-Ga bilayer precursors were fabricated by pulsed laser deposition（PLD） method and the CuIn1-xGaxSe2（CIGS） thin films were formed through selenization and heat-treatment of Se vapor.The influence of heat treatment temperature on the properties of CIGS thin film was discussed.We also studied the surface morphology,composition,phase structure and optical band gap with stylus profiler、SEM、EDS、XRD and UV-Vis absorption spectroscopy.It is found that the optimized fabrication parameters of CIGS thin films with good optical properties are that the ratio of nCu/（n_In+n_Ga）=0.98,nCu/（n_In+n_Ga）=0.28,the time of selenization is 60min,the temperature of selenization is 250 ℃,and the heat-treatment temperature is 550℃.The optical band gap of the CIGS film prepared under the optional conditions is 1.43eV,X-ray diffraction results indicate that the CIGS thin films are well crystallized,and there is single phase and chalcopyrite structure in the film.