The invention discloses a process for synthesizing high-purity polyphenylene sulfide resin. The high-purity polyphenylene sulfide resin is made of p-dichlorobenzene and sodium sulfide with certain crystal water, lithium chloride is used as a solubilizing assistant, and N-methyl-2-pyrrolidone is used as a solvent, so that the high-purity polyphenylene sulfide resin can be synthesized. The process includes that chemical raw materials such as oxygen-free deionized water, the sodium sulfide, the lithium chloride and the NMP (N-methyl-2-pyrrolidone) need to be added in a dehydration system before dehydration technological procedures are carried out, and then the p-dichlorobenzene is added into a synthesis system after heating dehydration is completely carried out on the synthesis system, so that condensation polymerization can be carried out. The process has the advantage that the high-purity polyphenylene sulfide resin synthesized and produced by the aid of the process can be widely applied to the fields of aerospace, electronic machinery, petrochemical engineering, foods, light industry, thermal power generation, cement industry, iron and steel manufacture, environmental protection, textile industry and the like.