Abstract In this study, the molecular structure and mechanical properties of titanium dioxide (TiO 2 )/polyisoprene (PI) composites were investigated using molecular dynamics simulation methods. Firstly, the models of TiO 2 particles and PI matrix were constructed and optimized using Materials Studio software. The molecular structure evolution of the material at different temperatures and loading conditions was obtained by Lammps simulation, and the interaction mechanism between TiO 2 particles and PI molecules was analyzed. The tensile and compressive mechanical properties of TiO 2 /PI composite materials were studied, and simulation results showed that the addition of TiO 2 particles significantly improved the mechanical properties of the composite material, increasing its elastic modulus and tensile strength. The mechanical behavior of TiO 2 /PI composite materials under different loading conditions was further elucidated. In addition, the influence of temperature on the mechanical properties of TiO 2 /PI composite materials was also studied. Simulation results showed that the composite materials exhibited good thermal stability and mechanical properties at lower temperatures. In conclusion, this study provides an in‐depth investigation of the molecular structure evolution and mechanical properties of TiO 2 /PI composites through molecular dynamics simulations, which provides theoretical guidance for optimizing their properties in practical applications. Highlights Explored titanium dioxide (TiO 2 )/polyisoprene (PI) composite mechanics at the molecular level. Revealed the interaction mechanism between TiO 2 particles and PI. Studied composite material mechanics under diverse loads. Stress–strain curves to analyze the deformation behavior. Studied temperature and strain rate effects on mechanical properties.