Abstract: This paper probes into the viscosity property, sands-carrying capacity, filtration property and steady rheological property of viscoelastic surfactant as fracturing fluid for CBM wells, and for the first time analyzes the mechanical parameters of coal samples before and after saturated by various fluid according to the acoustic time results. The results show that viscoelastic surfactants, VES-2-16 and VES-4-16, have good viscosity property and reach more than 30mPa·s at 170s-1, they also have stable structural viscosity at high shear rate, ceramic settling velocity in the type of viscoelastic surfactants ranges from 0.027% to 0.3% in clear water. The type of viscoelastic surfactants has no residue, large beginning filtration and small filtration coefficient. The coal samples of saturated liquid are more compressive and shearing resistance and the coal samples of saturated fracturing fluid also better than another of saturated water.