Abstract: This paper presents an experimental study on the axial compressive behavior of 36 heat-damaged square columns wrapped by basalt fiber-reinforced polymer (BFRP) sheets and 15 reference columns after different levels of heat damage. The test results indicate that the BFRP confinement can change the failure mode of heat-damaged square columns and significantly enhance the strength and deformation properties of these columns. For the heat-damaged columns wrapped with three layers of BFRP sheets, the axial strengths of these columns after exposuring to 200℃, 400℃, 600℃ and 800℃ are increased by 48%, 130%, 206% and 389%, respectively; and the corresponding axial deformation increases are 433%, 344%, 319% and 251%, respectively. The typical ultimate stress and ultimate strain models for fiber-reinforced polymer (FRP)-confined undamaged concrete are not suitable for FRP-confined heat-damaged concrete. Through establishing the hydrostatic pressure balance equation of the cylindrical FRP membrane as well as proposing the volumetric strain energy models of confined concrete and BFRP sheets, the basic formulas defined for the axial ultimate stress and axial ultimate strain of FRP confined fire-damaged concrete columns are modified. The temperature-dependent variables in the proposed formulas were determined based on the presented experimental results, and therefore, design-oriented models were established for axial ultimate stress and axial ultimate strain of FRP-confined heat-damaged square concrete columns.