The invention relates to a synthetic method of strongly basic anion exchange resin, and particularly relates to a synthetic method of high temperature-resistant strongly basic anion exchange resin containing a long-carbon chain alkylamine group. A crosslinked polystyrene white ball is adopted as a skeleton, chloromethyl ether is adopted as an alkylating reagent to graft benzyl chloride on the white ball skeleton by Fourier reaction, and amination reaction is carried out on the long-carbon chain alkylamine, so as to obtain the strongly basic anion exchange resin. The synthetic method has the advantages that the strongly basic anion exchange resin with relatively high heat stability can be synthesized by adopting a simple production technology and cheap materials, so that the strongly basic anion exchange resin can be applied to unit operation in a high-temperature environment, such as preparation of super-pure water in a semiconductor industry, high-temperature condensate refined treatment of a power plant, removal of silicic acid of water in a high-pressure boiler, and use under a high-temperature condition as a catalyst.