Large area monolayer molybdenum disulfide (MoS₂) film grown on silica/silicon substrate was synthesized using a catalyst perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) by the method of chemical vapor deposition. The properties of the monolayer MoS₂ film were characterized using a number of techniques. The optical microscope images show the film is uniform and continuous on a large scale. The 0.7 nm film thickness measured by atomic force microscope, as well as the difference of 20 cm⁻¹ between the two characteristic Raman peaks, all prove that the film is single layer. The strong photoluminescence spectrum and image as well as the x-ray diffraction indicate that the monolayer MoS₂ film has a good quality. The MoS₂ film synthesized under the same conditions without PTAS was also characterized as a comparison. The results show that the MoS₂ film tends to thicker without using PTAS, suggesting that PTAS can not only promote the formation of the MoS₂ seeding, but also induce horizontal growth of the MoS₂ film on the substrate.