To improve the fluidity and mechanical properties of the face concrete used in rockfill dam, the influence law of steel/polypropylene fibers on its performance was analyzed through expansion tests, three-point bending tests and compressive tests. The results show that the addition of fibers reduces fluidity, and the influence of steel fibers is more severe. When the total volume fraction of blending exceeds 1%, the expansion degree decreases by 15.3%, and T500 increases by 98.5%. The addition of fibers enhances the compressive and flexural strength of concrete. The compressive strength of the mixed group increases by 30.0% compared with the reference group, and the flexural strength increases by 35.4%. The synergistic effect of the mixed group is significant. Compressive strength has a strong linear relationship with flexural strength. The strength and ductility of steel/polypropylene fibers are enhanced through bridging cracks, and the bending load-displacement curve of the blended group shows ductility. Based on the comprehensive test results, the overall volume fraction of steel/polypropylene fiber blending should be controlled within 1%, which can take into account the requirements of fluidity and mechanical property optimization.