▎ 摘　　要

NOVELTY - Preparation method of poly (p-phenylene benzobisoxazole) (PBO) polymerization solution comprises (i) mixing 4,6-diamino-1,3-resorcinol hydrochloride (DADHB) and carboxylated graphene with an alkali solution and adding chloride salt to react to obtain a DADHB/carboxyl graphene polymer and (ii) adding the DADHB/carboxyl graphene polymer and terephthalic acid to a mixed solution of polyphosphoric acid and methanesulfonic acid, heating to remove hydrogen chloride and reacting to obtain the PBO polymerization solution, where the molar ratio of DADHB and terephthalic acid is 1-1.2:1. USE - The method is used for preparing poly (p-phenylene benzobisoxazole) polymerization solution, which is used in preparation of PBO fibers (all claimed). ADVANTAGE - The preparation method reduces the amount of DADHB and increases the relative molecular weight of the PBO polymerization solution. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for the PBO polymerization solution prepared by the above method.