The invention discloses a method of synthesizing 2-(2-chloroethoxy ethyl) acetal, namely 1,13-dichloro-3,6,8,11-tetraoxatridecane-13 or 1,14-dichloro-3,6,9,12-tetraoxatetradecan-14 by taking 2-(2-chloroethoxy) ethanol and aldehyde as raw materials. The 2-(2-chloroethoxy) ethanol, which is the material used in the method, is a by-product in the production of 2-ethylene chlorohydrin from ethylene oxide and hydrogen chloride, and the cost is lower. The product of the invention is a novel liquid polysulfide rubber synthesis monomer, the performances of the synthesized polysulfide rubber product are better than those of a traditional polysulfide product, the matching requirements of a domestic large aircraft and a domestic large ship on a special polysulfide sealant are met, and more options are provided for the production of the liquid polysulfide rubber.