The representative volume element (RVE) modeling of basalt fiber reinforced polypropylene composites (BF/PP) was carried out by Digimat software. The effects of fiber content, fiber aspect ratio and fiber orientation on mechanical properties of the composites were analyzed. The simulation results showed that the elastic modulus of BF/PP composites with basalt fiber mass fraction of 5%, 10%, 20% and 30% compared to the matrix material was increased by 16.43%, 79.08%, 214.03% and 406.01% , respectively. The effect of basalt fiber aspect ratio greater than 200 on the elastic modulus of BF/PP composites was relatively small. The elastic modulus of BF/PP composites decreased with the increase of basalt fiber orientation deviating from the load direction. The experiment results showed that the elastic modulus of BF/PP composites increased by 38% when the basalt fiber content increased from 5% to 30%. The error between the experimental results and the simulation results was 128.7%. The Digimat software accurately predicted the influence of different contents of basalt fibers on the mechanical properties of BF/PP composites, providing a reference for actual production.