To discuss the behavior of ultra-high performance concrete(UHPC)under a low-speed com-pressive impact,the parameters of continuous surface cap(CSC)model in the LS-DYNA are calibrated,based on the material characteristics of UHPC.The low-speed impact analysis model of UHPC using SHPB technology is established and verified with experimental results.On this basis,the effect on the dynamic in-crease factor(DIF)varying in the uniaxial compressive strength and strain rate of UHPC specimen under the low-speed impact is discussed.A regression formula to calculate DIF for UHPC is established.The re-sults are as follows:Based on appropriate parameter values,the established analysis model using the cali-brated CSC model for UHPC has an accepted accuracy.The variation trend of the stress ratio between the front-end and rear-end of UHPC specimen under different uniaxial compressive strengths is generally simi-lar,but the simulation effect demonstrates a downtrend with the increase of strain rate for the calibrated CSC model.The DIF value of UHPC increases with the increase of strain rate,but decreases with the in-crease of uniaxial compressive strength,indicating the clear strain rate and strength effects.The formula to calculate DIF for UHPC coupling with strain rate and uniaxial compressive strength can well agree with the analysis results and avoid overestimating the DIF values of UHPC to a certain extent,indicating certain ap-plicability for estimating the dynamic behavior of UHPC under a low-speed impact.