In order to improve the problem of high friction resistance at the front end and low viscosity at the tail end of fracturing fluid in shale reservoir fracture network volume fracturing，the steric hindrance of twin tail monomers with different carbon chain lengths，mean square terminal distance and mean square displacement of polymer materials were simulated based on molecular dynamics. The drag reducer LMA-DiC¹²AM-AM（LAD）was synthesized by micellar polymerization with lauryl methlacrylate （LMA），acrylamide（AM）and N，N-dodecyl acrylmaide（DiC¹²AM），then the structure was characterized. The rheological property，drag reduction and sand-carrying capacity of LAD solution were studied by rheometer and friction tester. The results showed that DiC¹²AM monomer had small steric hindrance，the best chain flexibility of polymer materials molecules，the best ability to bind water molecules，and the great drag reduction potential. LAD had good shear stability（viscosity＞75 mPa·s），shear recovery performance and sand-carrying capacity. The temperature-resistance capacity was up to 60 ℃ ，meanwhile the drag reduction rate reached 67.4%. LAD had both drag reduction and sand-carrying properties，which was basically consistent with the simulation result.