Cu2ZnSnS4（CZTS）thin films were deposited on Mo-coated soda lime glass substrates by magnetron sputtering and sulfurization treatment. The microstructure of thin films sulfurized at different temperatures was studied using different microstructural charaterizations such as X-ray diffraction （XRD）， scanning electron microscopy （SEM），transmission electron microscopy（TEM），high angle annular dark field（HAADF） imaging and X-ray energy dispersive spectrum（EDS） analysis. The results showed that crystallization of CZTS films synthesized at above 400 ℃ was enhanced with the increase of annealing temperature from 400~550 ℃，but decomposition reaction of CZTS films occurred at 600 ℃. Films morphology was influenced by the temperatures greatly，the size of grains close to the surface of the thin films was large and the size of grains close to the Mo substrate was small. The CuS phase was observed on the surface of the thin films based on the rich of Cu and S，while the contents of Zn and Sn were rich close to the Mo substrate at relatively low temperatures. With the increase of temperatures，crystallization of CZTS films was enhanced with Cu，Zn，Sn and S gradual diffusion，and the grains of CZTS grew up as equiaxial crystals. Twins were formed in grains of CZTS.