Abstract: Through the strength tests of fiber reinforced granulated blast furnace slag concrete in high temperature, the influences of temperature, replacement ratio of slag powder, steel fiber content and polypropylene fiber content on the strength of concrete in high temperature are analyzed. The results indicate that the strength of concrete deteriorates as the temperature grows, the demarcation point of the deterioration of compressive strength is 400℃. The splitting tensile strength and flexural strength decrease along the inclined straight line as the temperature grows, and the decreasing range is more than that of the compressive strength. The addition of steel fiber can evidently increase the strength of fiber reinforced granulated blast furnace slag concrete in high temperature. Both polypropylene fiber and slag powder have the effect on the bursting and strength deterioration of concrete in the high temperature. Based on the statistical analysis, the calculation formulas of strength of fiber reinforced granulated blast furnace slag concrete are put forward which concerns the effect of temperature and mixing amount of steel fiber.