The invention discloses a water-soluble fluorescent polymer containing pyridyl 1,3,4-oxadiazole and a synthesis method thereof, which specifically includes: (1) acrylic acid and 4-formylhydrazide pyridine in a dry phosphorus oxychloride environment In the system, negative pressure heating and reflux reaction for 5-6 hours to obtain fluorescent monomers; (2) Initiate polymerization of the synthesized fluorescent monomers, acrylic acid and maleic anhydride aqueous solution to synthesize water-soluble fluorescent monomers with a viscosity average molecular weight of 5000-10000 Label the aqueous solution of acrylic-maleic acid copolymer. The present invention utilizes unsaturated carboxylic acid containing carbon-carbon double bond and formic hydrazide of 1,3,4-oxadiazole containing pyridyl group to synthesize fluorescent monomer containing unsaturated carbon-carbon double bond, and further polymerizes into water-soluble fluorescent monomer Labeled copolymer; the method is simple and easy to operate, has low excitation energy, good concentration fluorescence linearity, mild reaction conditions, safe and environmentally friendly synthesis process, and is easy to realize large-scale industrial production.