Aiming at the flame retardant modification of epoxy resin by liquid winding process， the effect of flame retardant addition amount on the properties of resin and composite material was studied. The results show that the viscosity of the resin decreases slightly with the addition of flame retardant， and the curing reactivity does not change significantly. With the increase of flame retardant content， the tensile strength of epoxy resin is basically stable but the impact strength is decreases. The impact strength of epoxy resin added with 30 phr flame retardant is decreased by 44.1% compared with 0 phr. In addition， with the increase of flame retardant content， the thermal decomposition stability of resin is improved， but excessive addition of flame retardant components is not conducive to the stable formation of carbonized layer. According to the above research， the resin system with 20 phr flame retardant additive has the best flame retardant effect， the 50 W vertical combustion test results reach V-0 level， and the mechanical properties have a good retention rate. The tensile strength of NOL ring prepared by modified resin on T700SC reached 2 790 MPa， and the interlayer shear strength is 50.7 MPa. The modified resin and fiber have good interfacial bonding.