The invention discloses a high-salt-resistant viscoelastic surfactant cleaning
fracturing fluid and a preparation method thereof. The
fracturing fluid contains a cationic surface
active agent, and thestructural formula of the cationic surface
active agent is shown as the following formula. In the formula, R<1>' is selected from saturated alkyls with a
carbon number n meeting a relationship of 16<=n<=24, unsaturated alkyls with a
carbon number n meeting a relationship of 16<=n<=24, and a compound as shown in the following formula, wherein R<1> is selected from saturated alkyls with a
carbon number n meeting a relationship of 16<=n<=24, and unsaturated alkyls with a carbon number n meeting a relationship of 16<=n<=24; and R<2> is selected from saturated alkyls with a carbon number C meetinga relationship of 3<=C<=7, unsaturated alkyls with a carbon number C meeting a relationship of 3<=C<=7, and short-chain alkylbenzene (C<=5). The cationic surfactant has good resistance to
inorganic salts, and the principle is that the R<2>
substituent groups block mutual proximity between polar head groups of the cationic surface
active agent under a high-mineralization-degree condition, and thenprecipitation of the cationic surface active agent is avoided, so that the
micelle continues keeping a dense three-dimensional
network structure, and tackifying performance is improved.