Abstract: In order to study the influence of acicular and flaky aggregate on the mechanical properties of concrete, a three-dimensional numerical model of concrete random aggregate at the meso-level was established in this study.The particle shape and volume ratio of deformed particles in coarse aggregate were taken as variables, the failure process of two graded aggregate concrete cubic model with acicular and flaky aggregate under uniaxial tension and uniaxial compression load was simulated.The results show that:(1) The tensile and compressive strength of concrete will decrease with the increasing of acicular and flaky aggregate content.The effect of acicular and flaky aggregate content on the tensile strength of concrete is smaller than that of compressive strength.(2) The influence of acicular and flaky aggregate on the failure of concrete under uniaxial tensile and compressive loads is mainly related to its arrangement.The aggregate with larger transverse aggregate-mortar interface plays a dominant role in the generation and development of concrete tensile damage.The surface of acicular and flaky aggregate vertically or approximately vertically placed in concrete is more likely to crack under uniaxial compressive load.(3) The acicular and flaky aggregate have adverse effects on the strength and failure process of concrete, and the influence from big to small is flaky aggregate > acicular aggregate > mixed aggregate.