Abstract: The antiswelling agent which is currently used in fracturing fluid is disadvantageous with large consumption, poor compatibility and inconvenient preparation on site.To solve these problems, three-step method was used to synthesize liquid antiswelling agent of organic cation type with high antiswelling rate and good compatibility.The optimal reactant proportion, reaction temperature and reaction time of intermediate product and the optimal formula of end product were determined.It is shown that when the mass fraction of antiswelling agent is 0.3%, the antiswelling rate of fracturing fluid with drag reducing solution is 70.5% and its drag reduction rate is unchanged.Compared with similar antiswelling agents available in current markets, the antiswelling agent of pilot production is 17%-33% higher in antiswelling rate.It is applied actually to multiple-hole-interval fracturing in Xinjiang and Chongqing, presenting good compatibility and antiswelling performance.It is demonstrated that this newly developed antiswelling agent can satisfy the requirements on antiswelling and continuous mixture of fracturing fluid.