Objective To prepare the flame-retardant spray polyurea coating with similar performance with the spray polyurea coating in mechanical property, thermal stability and surface appearance. Methods The spray polyurea coating was prepared mainly from isocyanates (A component), polyether polyols and amine chain expanding agent (B component) by high-pressure airless spraying. We added the solvent flame retardants in A component, and the inorganic filler type flame retardant in B component. The method to prepare the flame-retardant spray polyurea coating was the same as that of the spray polyurea coating. Limiting oxygen index (LOI) test, tensile machine and differential scanning calorimetry (DSC) were taken to evaluate the flame retardant property, mechanical property and thermal stability of the spray polyurea coating and the flame-retardant polyurea coating, respectively. The two coatings were also analyzed by scanning electron microscope. Moreover, flame ignition was employed to test the flame retardant property of the two coatings directly. Results The LOI of the coating containing flame-retardant could be increased from 18% to 28%, the tensile strength was decreased from 12.5 MPa to 11.3 MPa, and the elongation from 430% to 422%. Although the mechanical strength of polyurea flame retardant coating was declined, the decline rate was not very small and still in the range of use. Furthermore, the LOI of the flame-retardant spray polyurea coating was elevated, and the thermal stability and the surface appearance were excellent. The flame-retardant property of the coating was good, which was self extinguishing, generating no smoke and no dripping after flame ignition. Conclusion The addition of flame-retardant could effectively improve the flame-retardant performance, and we successfully prepared the flame retardant spray polyurea coating.