A method of high performance liquid chromatography with solid phase extraction using covalent organic polymers（COPs） was developed for the analysis of three fluorescent whitening agents（FWAs） in flour.The COPs with satisfactory adsorption performance were successfully synthesized by the Schiff base reaction of 1,3,5 triformylphloroglucinol and 2,6 diaminopyridine at room temperature,using BiCl3 as catalyst,then characterized by Fourier transform infrared spectroscopy（FT-IR） and nitrogen adsorption experiment.Results showed that the imine linked COPs with good specific surface area were successfully constructed.The synthesized COPs were used as the SPE sorbent in the extraction of three FWAs in flour,and finally the three FWAs were determined by high performance liquid chromatography（HPLC）.Under the optimum conditions,the method exhibited good linear relationships for the analytes in the range of 1-100 μg·L-1 with limits of detection（LODs,S/N=3） and limits of quantitation（LOQs,S/N=10） of 015-027 μg·kg-1 and 050-089 μg·kg-1,respectively.The recoveries for three FWAs in flour at three spiked levels ranged from 812% to 102% with relative standard deviations（RSDs） of 43%-127%.The developed method was simple,accurate and sensitive,and could be applied in the determination of FWAs in flour samples.