WS2 films with different structures and space lubricating oils are combined to construct the WS2/oils composite lubricating systems. Friction and wear of the WS2/oils systems are mainly studied in vacuum. Results show that WS2/P201 systems display much lower friction coefficient (mu asymptotic to 0.06) than WS2/PFPE systems (mu asymptotic to 0.11), which is found to depend on lubricity of oils. Noteworthily, the dense WS2 film of the WS2/PFPE systems has the lowest wear rate of about 5.6 x 10(-6) mm(3).(N.m)(-1) although friction coefficient of the system is high. This is due to good wettability of PFPE on the dense WS2 film, whose contact angle is low to 5. Eventually, the lubricating mechanism of the WS2/oil systems are revealed via correlating interaction between oil molecules and WS2 crystals.