The apparent characteristics and mechanical properties of ultra-high performance concrete reinforced by different fibers were studied by using high temperature heating and high temperature compression strength tests on the cylinders. Aiming at different temperatures, fiber content and fiber types, 108 specimens of ultra-high performance concrete cylinders were prepared, and uniaxial compression tests were carried out at 6 target temperatures (20℃, 200℃, 400℃, 600℃, 800℃, 1000℃). The effects of single steel fiber, mixed steel fiber of different lengths, mixed steel fiber and polypropylene fiber, mixed steel fiber and polyethylene fiber on high temperature cracking and compressive strength of ultra-high performance concrete were compared. The results show: with the increase of temperature, the damage degree of ultra-high performance concrete becomes more serious. After high temperature action, the mixed steel fiber and polypropylene fiber ultra-high performance concrete can also maintain good integrity and high compressive strength, and can still maintain 30% residual strength after high temperature action at 1000℃. With the increase of temperature, the compressive strength of ultra-high performance concrete increases and then decreases, and the ductility of ultra-high performance concrete is enhanced by high temperature.