As the strength of concrete increases, its ductility decreases, making it more prone to cracking and adversely affecting durability. Therefore, the study of ultra-high strength, ultra-high toughness cement-based composite holds significant importance. This study combined the design principles of ultra-high-strength concrete and strain-hardening cement-based composites, using polyethylene (PE) fibers as reinforcing materials to develop ultra-high strength strain hardening cement-based composite (UHP-SHCC). The mechanical properties of UHP-SHCC were comprehensively evaluated using the analytic hierarchy process-criteria importance through intercriteria correlation (AHP-CRITIC) hybrid weighting method, resulting in an optimized mix design with the following proportions: 25% (mass fraction) silica fume, 20% (mass fraction) mineral powder, a sand binder ratio of 0.1, 2.00% (volume fraction) PE fiber, and a water binder ratio of 0.18. Additionally, corrugated steel fibers and hooked-end steel fibers were combined with PE fibers to explore the synergistic effects of the two types of fibers. The results indicate that the inclusion of steel fibers significantly enhances the initial cracking tensile strength of UHP-SHCC. Furthermore, after the failure of PE fibers, steel fibers effectively provide bridging action, delaying specimen failure, increasing the ultimate tensile strain, and reducing crack width in UHP-SHCC.