［Objective］To improve the application efficiency（viscosity issues）and fire-retardant performance of solvent-free epoxy fire-retardant coatings in engineering applications.［Methods］ Orthogonal experiments were conducted to determine the optimal ratio. The application viscosity andfire-retardant performance of the solvent-free epoxy system were systematically investigated usingscanning electron microscopy（SEM） and thermal insulation efficiency test furnaces.［Results］ Solvent-free epoxy fire-retardant coatings（System1） were prepared using bisphenol A epoxy resin（NPEL-128）as the film-forming agent and polyamide resin（PA）as the curing agent. With a mixed viscosity of 2. 6 Pa·s，it was suitable for trowel application. At a coating thickness of 13. 6 mm，it achieved a fire resistance rating of 3 hours and an expansion ratio of 7 times. Solvent-free epoxy fire-retardant coatings were prepared with NPEL-128/bisphenol F epoxy resin（NPEL-170）/polypropylene glycol diglycidyl ether（PPGDGE） as the film-forming agent and amide-based amine resin as the curing agent（System2）. With a mixed viscosity of 1. 5 Pa·s，it was suitable for spray application. At a coating thickness of 7. 7 mm，it exhibited a fire resistance rating of 2 hours and an expansion ratio of 15 times.［Conclusion］ Both systems could effectively improve construction efficiency and offerexcellent fire-retardant performance.