Abstract: To elucidate the impact of recycled aggregate replacement ratio on the dynamic compressive performance of steel fiber reinforced recycled aggregate concrete (SFRAC), this study developed a three-dimensional mesoscopic numerical model of SFRAC using ABAQUS and conducted systematic uniaxial static and dynamic compression tests under varying replacement ratio. The research investigated how the replacement ratio affects SFRAC's compressive strength, strain rate effect, and size effect, performed regression analysis based on Bažant's size effect law, and proposed a dynamic size effect correction formula accounting for recycled aggregate replacement ratio. Results demonstrate that SFRAC compressive strength significantly decreases with increasing replacement ratio under quasi-static conditions, with the specimen with 100% replacement ratio exhibiting a strength reduction of 16.75%. Both strain rate effect and size effect intensify with higher replacement ratio, while increased strain rates markedly attenuate size effect. The dynamic size effect correction formula accounting for recycled aggregate replacement ratio, derived from Bazant's law, shows relative errors between predicted and actual values ranging from 0.09% to 7.02%, providing a theoretical foundation for SFRAC applications under dynamic loads and in large-scale structures.