In order to reduce the friction of fracturing construction and improve the effect of unconventional reservoir fracturing, based on the systematic investigation of domestic and foreign literatures on drag reducing agents used in fracturing, the types and mechanism of drag reducing agents were reviewed, the influencing factors of drag reducing performance were analyzed, the field application of drag reducing agents and the main existing problems of drag reducing agents were introduced, and the future development direction of drag reducing agents was proposed. The results show that the main problems of the current commonly have problems such as high cost, unstable performance, and unclear drag reduction mechanisms. The multi-functional nano-composite drag reducer with low cost, low damage to reservoir and high drag reduction performance will be the focus and hot spot in the future research of drag reduction agents. Through the comprehensive study of drag reducing agents, it can provide feasible help for improving the performance of current drag reducing agents, the research and development of new drag reducing agents and the exploitation of unconventional oil and gas.