Due to the development of new engineering materials and high-speed cutting, cutting fluid plays an important role in machining. Commonly, the use of cutting fluid can decrease cutting temperature, reduce the friction between tool and workpiece, extend tool life, and improve machining efficiency and surface quality. These effects of cutting fluid were mainly obtained from its basic functions including cooling, lubrication, corrosion protection, and cleaning. According to the review of the researches in cutting fluids applied in metal cutting process, the available researches mainly focused on the application strategies and penetration capability, processing performance, new types of environmentally friendly cutting fluids, and preliminary machined surface quality. This article also suggests that the effect of cutting fluid on machined surface quality and performance will become an important research direction. There is a matching problem between the cutting fluids and the workpiece materials. Further research on effect of cutting fluids on machined surface should include physical and chemical mechanism of the cutting fluid, action mechanism on fresh machined surface during machining process, action mechanism in the period of long-term service, stability of the composition and physical and chemical properties, and evaluation method of the effective use of cutting fluid.