WSx solid lubrication films are deposited on monocrystalline silicon substrates by pulsed laser deposition (PLD). The composition, morphology and microstructure of the films are characterized by energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and X-ray diffractometer respectively. The tribological behavior is investigated using a ball-on-disk tribometer in atmosphere (relative humidity is 50%~55%). The results show that the composition of the film was controllable while the atom fraction ratio of sulfur to tungsten ranges from 1.05 to 3.75 and the friction coefficient ranges from 0.1 to 0.2. The friction coefficient and film quality deteriorates dramaticly when the ratio of sulfur to tungsten exceeds 2.0. It is well-established that the rank of main influence factors related to the ratio of sulfur to tungsten of the WSx films are argon pressure, temperature, target-substrate distance and laser flux by orthogonal test, and a near-stoichiometric WSx film with dense structure could be grown under optimized growth conditions, including deposit temperature at 150 ℃, distance between target and substrate at 45 mm and laser flux at 5 J/cm2 and argon pressure at 1 Pa.