CZTS thin films were fabricated through sulfurization of sputtered alloy precursors. The properties of CZTS films obtained at sulfurization time of less than 2 hours and at H2S concentrations of higher than 15% were investigated. Sulfurization time of 30 min, 60 min and 90 min and H2S concentrations of 20%, 40% and 60% have been chosen for the sulfurization process. It has been found that Cu poor and slightly Zn rich CZTS films can be obtained at all of those sulfurization time and H2S concentrations. Changing the sulfurization time or H2S concentrations won't change the compositions of sulfurized films. Minor SnS coexist with the dominate CZTS although the films are Zn rich and the distributions of Sn and S along the depth of the films are uniform. The films sulfurized at H2S concentration of 20% have the biggest grain size of exceeding 2 μm and obvious columnar CZTS grains can be observed across the whole cross-section.