In order to investigate the adaptation of ultrasonic test in evaluating the performance of reactive powder concrete (RPC) after high temperature exposure, the high temperature tests under 100 ℃, 200 ℃, 300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃ and 800 ℃ were performed. The relationship between the four parameters (relative wave velocity, damage degree, relative frequency and relative amplitude) and temperature as well as compressive strength loss rate was analyzed. The microstructure of RPC was also studied by scanning electron microscopy (SEM) technique after exposure to high temperature. The results showed that adopting the parameters of damage degree and relative velocity to evaluate the performance of RPC after high temperature was better than adopting the parameters of relative frequency and relative amplitude. The correlation of the fitting value of damage degree with experimental value was the largest, which can accurately reflect the damage degree of RPC. On the contrary, the fitting value of relative frequency and relative amplitude showed little correlation with the experimental value. With the increasing of the elevated temperature, the internal defects of RPC exacerbated, and the cracks at the bonding interface of fiber and the matrix occurred gradually, which illustrated that the micro-structure of RPC deteriorated constantly and the loss rate of compressive strength increased gradually.