In recent years, transition metal dichalcogenides materials represented by monolayer molybdenum disulfide (MoS₂) have aroused great interest due to their excellent optical and electrical properties. The synthesis method of high-quality monolayer MoS₂ film is a key problem for scientific research and industrial application. Recently, researchers have proposed a salt-assisted chemical vapor deposition method for growing the monolayer films, which greatly promotes the growth rate and quality of monolayer film. By using this method, we design a growth source of semi-enclosed quartz boat, and successfully obtain high-quality monolayer MoS₂ films by using the double auxiliary action of sodium chloride (NaCl). Scanning electron microscopy shows the excellent film formation, and the photoluminescence spectra show that the luminescence intensity is significantly higher than that of the sample grown without NaCl. The NaCl double-assisted growth method proposed in this study can reduce the growth temperature of MoS₂, shorten the growth time, and improve the optical properties of the films. Besides, the operation is simple and the cost is low, which provides an idea for growing the large-scale two-dimensional materials.