Abstract: To investigate the effect of steel fibers on the shear performance of prestressed ultra-high performance concrete (UHPC) rectangular beams, four-point loading tests were conducted with variables including fiber content, size, and shape, focusing on load-deflection behavior, crack propagation, and failure modes. The sensitivity of shear capacity to fiber parameters under different design conditions was systematically explored using a plastic damage model by numerical simulations. Results show that the shear capacity improves by 10.7% when the fiber content increases from 1% to 2.5%, and hooked steel fibers can improve the structural ductility by 41.7% compared to straight steel fibers. Parametric analyses indicate that the effect of fiber content is more significant under larger shear span-to-depth ratios or lower reinforcement ratios. The American code and ultimate equilibrium method predict the shear capacity with an average error of less than 5%, while the French and German codes yield conservative estimates, despite accounting for fiber contributions.