The biodegradability,lubricity,antiwear and friction reduction properties,thermostability,anticorrosion and antirust properties of liquid paraffin were investigated with hydroxyl imidazoline(HIZ)as lubricating oils biodegradation promoter.The results indicate that the HIZ as biodegradation accelerant can enhance the biodegradability of liquid paraffin effectively,it is because the HIZ can decrease the oilwater interfacial tensions and accelerate microbial growth.HIZ can also improve the friction reducing property,anticorrosion and antirust property of liquid paraffin in a certain degree,and is almost unaffected to the thermostability of liquid paraffin.