Abstract: The aqueous medium reaction method is currently mainly used in the biomedicine field, and there are few reports in the research field of functional polymer materials. The synthesis of multifunctional benzoxazole resins in aqueous medium was studied in this paper. Four monomers (DAR-C, DAR-N, LAR-C and LAR-N) containing benzoxazole structure were designed and synthesized. A series of thermosetting benzoxazole resins were obtained through the curing process, and their structure and chemical composition were characterized by EI-MS and FT-IR. The curing characteristics were studied by DSC. The heat resistance and dielectric properties were characterized by TGA and broadband dielectric spectrometer. The results showed that cracking benzoxazole structure and increasing free volume could effectively improve the solubility of the resins. In addition, cyanide resins with higher nitrogen content had better solubility. The introduction of the benzoxazole structure effectively improved the heat resistance of the resins. Among them, the T_d5 of PLAR-N and PDAR-N in the air were 612 ℃ and 600 ℃, respectively. Biphenyl formed a more complete cross-linking system and had higher curing reactivity than single benzene. With the improvement of the cross-linking system, the dielectric properties of the resin had also been greatly improved. At 1 kHz, the dielectric constant of PLAR-N was 2.24. and the dielectric loss was 0.008.