In order to realize the direct preparation of slick-water with high salinity brine for volume fracturing，and to solve the high cost and environmental pollution problems of conventional W/O inverse emulsion friction reducer. An environmentally friendly salt-tolerant friction reducer PADD was prepared through introducing polar hydrophilic monomer and salt-tolerant cationic monomer into the polymer by emulsion dispersion polymerization method. The solubility，temperature resistance，resistance reduction performance and damage to the core of PADD were investigated，respectively，and the field application of PADD slick-water was mentioned. The results showed that PADD with mass fraction of 0.1% could be quickly and uniformly dispersed in clean water，40 g/L and 80 g/L mineralized water，respectively. Under the condition of high salinity（80 g/L），the molecular structure of PADD remained stable. The PADD solutions with mass fraction of 0.1% under three different salinities were aged for 72 h at 80℃，and the viscosity retention rate was greater than 90%，the drag reduction rate was above 70%，and there was less damage to the core. The high-salinity-resistant slick-water prepared with the flowback fluid using PADD as the main agent has been successfully applied in Wei 202H16.