In this paper, perlite was used as a kind of modifier to prepare waterborne fire resistive coatings for steel structure. The influence of perlite on the properties of the fire resistive coatings was investigated with the help of thermogravimetric analysis (TGA), micro-scale combustion calorimetry (MCC) and fire protection test. The TGA results showed that the char residue weight of the coatings was increased when perlite was loaded and the anti-oxidation performance was enhanced as well and MCC data indicated the addition of perlite reduced the peak heat release rate and total heat release. After the fire protection test, the results confirmed that the fire resistant time of the coating coated with 5 wt% perlite increased up to 114.4 min when the temperature of the sample boards’ backside reached 500?C.