English：

To study the change law of mechanical properties of ultra⁃high performance concrete (UHPC)mixed with fibers, the compressive strength and flexural strength of UHPC mixed with single fiber anddouble fiber were studied by an indoor test method based on a high⁃rise residential building project inChongqing. The results indicate that under the conditions of single fiber and a period of 56 days, whenthe single content of basalt fiber is 0. 38%, the single content of glass fiber is 0. 38%, and the singlecontent of polypropylene fiber is 0. 18%, the compressive strength and flexural strength of basalt fiberUHPC, glass fiber UHPC, and polypropylene fiber UHPC are the largest. Under the conditions ofdouble⁃doped fiber and a period of 56 days, when the content of basalt fiber is 0. 38% and the content ofglass fiber and polypropylene fiber is both 0. 18%, the mechanical properties of basalt⁃glass hybrid fiberand basalt⁃polypropylene hybrid fiber UHPC can be effectively improved. In the design of buildingstructures, the section size, reinforcement method, and connection structure of components should bereasonably determined according to the mechanical characteristics of basalt⁃glass hybrid fiber and basalt⁃polypropylene hybrid fiber UHPC to improve the utilization rate of structural space.