Abstract: Structural fire safety design is one of the key issues of circular steel tube confined reinforced concrete (STCRC) columns. Although an increasing number of studies are being conducted on the fire behaviours of circular STCRC columns, research and design on the fire performance of such columns with fire protection are still insufficient. The existing design method of high-temperature buckling resistance in current industry standard is not consistent with the corresponding method at ambient temperature. The design formulae for fire-protected circular STCRC columns in this standard are of no clear physical meaning. Using the ABAQUS software, this paper presents numerical simulations of the thermal distribution and fire resistance of circular STCRC columns with fire protection under the ISO 834 standard fire condition. The effects of key parameters such as load ratio, cross-sectional dimension, slenderness ratio and thickness of protection on the fire resistance of circular STCRC columns are studied. Practical formulae are proposed to calculate the temperature profiles of the steel tube, rebars and concrete core. The results show that with the increase of the fire protection thickness, the fire resistance of the column increases approximately linearly. Based on extensive parametric studies, design methods are developed for determining the compressive resistance and buckling resistance of protected circular STCRC columns at elevated temperatures, which could be used to calculate the fire protection thickness required for circular STCRC columns to reach different fire resistance rates. This method remains consistent with the design equations of ambient-temperature load-bearing capacity in the current standard.