The invention belongs to the technical field of polymer synthesis and specifically relates to an automatic synthetic device of a high-throughput polymer database and a method thereof. The synthetic device of the invention comprises a computer control system, an injection system, a mixing system, a reaction system and a product collection system. According to the method, (methyl)acrylic ester, acrylamide and styrene and its derivative are used as monomers, thiocarbonic ester, alkyl halide and the like are used as initiators, a polar solvent is used as a reaction solvent, a nonpolar solvent which is immiscible with the reaction solvent is used as a current-carrying solvent, segmented droplets are formed in a transparent reaction tube, and by heating or heating initiated polymerization and through computer control, automatic synthesis of multiple homopolymers or copolymers is realized. The polymerization result shows that the flow polymerization method has good controllability to number-average molecular weight and molecular weight distribution of the polymers, has advantages of simple operation wide range for monomers and high polymerization reaction rate, and can realize high-throughput screening and large-scale polymer synthesis by combination with the computer automation technology.