Vacancy structural defect effects on the lattice thermal conductivity of silicon thin films have been investigated with non-equilibrium molecular dynamics simulation.The lattice thermal conductivities decrease with increasing vacancy concentration at all temperatures from 300 to 700 K.Vacancy defects decrease the sample thermal conductivity,and the temperature dependence of thermal conductivity becomes less significant as the temperature increases.The molecular dynamics result is in good agreement with the theoretical analysis values obtained based on the Boltzmann equation.In addition,theoretical analysis indicates that the reduction in the lattice thermal conductivity with vacancy defects can be explained by the enhanced point-defect scattering due to lattice strain. Vacancy structural defect effects on the lattice thermal conductivity of silicon thin films have been investigated with non-equilibrium molecular dynamics simulation. The lattice thermal conductivities decrease with increasing vacancy concentration at all temperatures from 300 to 700 K.Vacancy defects decrease the sample thermal conductivity, and the temperature dependence of the thermal conductivity becomes less significant as the temperature increases. The molecular dynamics result is in good agreement with the theoretical analysis values ​​obtained based on the Boltzmann equation. In addition, the theoretical analysis indicates that the reduction in the lattice thermal conductivity with vacancy defects can be explained by the enhanced point-defect scattering due to lattice strain.