The modification of ZnS by doping method is one of the important directions in the research of ZnS nano materials. Doping of transition metal ions in the ZnS matrix has attracted much attention in recent years. Doping transition metal ions can modulate the emission region of ZnS, and improve the efficiency of fluorescence. The doping concentration in ZnS has determined the distribution, absorption, excitation, emission, and structural properties of particles. Due to ZnS:Co crystal materials have the best characteristics: the stability of the mechanical properties, high emission cross section and wide bandgap tuning at room temperature. So the ZnS:Co film is grown by pulsed laser deposition and the near infrared spectrum properties have analyzed that have researched in theory and experiment. We change the pressure in the vacuum chamber by controlling the pressure of the argon gas to fabricated the ZnS:Co film by PLD, at the same time, we chose three kinds of materials as the substrate of the thin film, and compared the characteristics of the thin films. This method has the advantages of short fabrication time and material saving, so it is good for to detect and research the optical properties of the films of ZnS:Co. A variety of film detection of X-ray diffraction, laser particle size analyzer, UV-Vis spectrophotometer, fluorescence spectrophotometer, morphology, the particle size and optical properties of the samples have tested. From the results, the infrared transmittance of the Co doped ZnS is almost above 90%, and the transmission capacity increases with the increase of pressure. The film thickness decreases with the increase of pressure and there is a sharp peak in absorption spectrum, this point has important significance for studying photoluminescence of the near infrared spectrum.