Abstract：A water soluble drag reduction agent (WDRA-M) applied in slick-water fracturing fluid was prepared by inverse emulsion polymerization. The chain flexibility was increased due to the introduction of long chain hydrophobic monomer (long chain methacrylates, WLHM). Dynamic Light Scattering (DLS), slick-water friction tester and dynamic rheometer were used to characterize the particle size and distribution, drag reduction efficiency and rheology properties of WDRA-M. The particle size analysis of WDRA-M shows its average particle size is 76.95nm and PDI is 0.108, which indicates the uniform distribution of WDRA-M. The drag reduction efficiency can be up to 62% at the optimum addition 0.7g/L. WDRA-M displays a non-Newtonian behavior, and the value of storage modulus (G', 0.783 Pa) is larger than that of loss (G'', 0.354 Pa), which illustrates an obvious elastic behavior of WDRA-M. It can reduce the friction resistance. The apparent viscosity is decreased from 43.46 mPa•s to 38.66 mPa•s, and the apparent viscosity retention rate is 89.0% when the shear rate was 170s-1, the shearing time 30 min at 25℃. The field application results show that the drag reduction efficiency of WDRA-M is 42.5% higher than guanidine gum, and 12.5% higher than foreign similar product at the displacement of 3.5m3/min.