In order to explore the influence of the Oils on Water(OoW) cutting fluids on the cutting force in turning,and obtain more suitable cutting parameter，the effect of the cutting parameters such as cutting speed,feed rate and depth in cutting on the main cutting force when cutting 45 carbon structural steel was investigated through orthogonal test.The empirical formula of cutting force was obtained based on the multiple linear regression analysis of force data.The results show that，although the change range of the main cutting force in OoW cutting is larger than dry cutting,the main cutting force in OoW cutting is reduced obviously when selecting a higher cutting speed,lower feed rate and greater depth in cut.