In order to study the variation regularity of the properties of steel fiber reinforced concrete and ordinary concrete when the actual project was in fire, through the MTS electro hydraulic servo material testing system and its supporting high temperature furnace, the strain curves of two types of concrete under high temperature were studied; at the same time, the load of 30% of the limit compressive stress was applied to the 2 types of concrete and the value was maintained, the high temperature strain test of steel fiber reinforced concrete and ordinary concrete under constant load was carried out, the acoustic emission technology was used to perform real time tracking and online monitoring of the temperature increase and constant temperature process. The result shows that under temperature constant load coupling action, the strain of steel fiber reinforced concrete is smaller than that of the ordinary concrete at the heating section of the target temperature, its ability of resisting destruction and deformation is stronger; the strain at loading damage is larger than that of the ordinary concrete, its ductility is better; the ringing accumulative count of steel fiber reinforced concrete is higher than that of the ordinary concrete, the addition of steel fiber can delay the damage of concrete.