To evaluate the crater damage effect of cylinder charge contact explosion on steel fiber reinforced concrete (SFRC) structures, a numerical model of an SFRC target was developed by the using the smooth particle Galerkin method and a structured arbitrary Lagrange-Euler (SPG-S-ALE) fluid-structure interaction algorithm. The failure modes and damage of the SFRC target under different charge mass Q and length-to-diameter ratios l/d were investigated. Based on contact explosion theory and dimensional analysis, cratering coefficients K₁ and K₂ were introduced to develop predictive models for the crater diameter D and depth H as functions of the effective charge mass Q_e. The results indicate that under the combined effects of charge mass and length-to-to-diameter ratio, the primary failure mode of the SFRC targets is cratering damage. Under constant charge mass conditions, as the l/d ratio increases from 1 to 5, both the crater diameter D and depth H decrease by approximately 50%. Within the range of effective charge Qₑ less than 16 kg, the K₁ and $\sqrt{K_2}$ exhibit a power-law decay with increasing effective charge mass, while the crater diameter D and depth H show a power-law growth. For a given effective charge mass Qₑ, the cratering effect is more concentrated on the expansion of the crater diameter. The developed predictive model allows for rapid and reasonably accurate calculation of crater dimensions in SFRC with different strength grades and effective charge mass, providing a theoretical basis for the blast-resistant design of SFRC structures.