Ethyl (3aR,7R,7aR)-2,2-dimethyl-7-((methylsulfonyl)oxy)-3a,6,7,7a-tetrahydrobenzo [d][1,3]dioxole-5-carboxylate is a key intermediate of oseltamivir, and its crystal structure and density functional theory (DFT) studies are conducive to exploring more reaction pathways for industrial applications. In this paper, the title compound was synthesized by esterification, condensation and sulfonylation from shikimic acid as the starting material. Its single crystal was obtained by solution crystallization and crystallographic analysis. The optimal structure and frontier orbital energies were calculated using the DFT in the B3LYP/6-311+G(2d, p) mode. The molecular structure optimized by DFT was compared with the crystal structure determined by X-ray single crystal diffraction, which provided similar results. The electrostatic formula and the frontier molecular orbitals of the molecule were further studied by using the DFT to reveal the physicochemical properties of the investigated compound.