The light hydrocarbons of oils play an important role in their geochemistry, especially in mixed oils. The database of the Key Laboratory of Petroleum Geochemistry, China National Petroleum Corporation has accumulated 824 oil sample records. The oil samples represent most of the oil areas of China. In this paper the light hydrocarbons of salt lake derived oils from Jianghan basin, China, were studied. These oils are characterized by high toluene contents and high K 1 [K 1 =(2-MH+2,3-DMP)/(3-MH+2,4-DMP)] values. The reason is unclear but may be related to the high salinity environment of the source.