Near-infrared spectroscopy is mainly the overtones and combination bands absorption spectra of organic molecules, which are generated by the overtones and combination bands of hydrogen-containing groups such as C—H, N—H, O—H, etc., which can obtain molecular structure, composition, state and other information. This technology is an important method for studying the vibration information of hydrogen-containing groups in organic matter and is often used for qualitative and quantitative analysis of biological substances such as food and crops. The research objects in the biochemical field also have hydrogen-containing groups. These hydrogen-containing groups have strong absorption frequency characteristics, are less affected by the internal and external environment of the molecule, and have more stable spectral characteristics in the near-infrared spectrum. This technology can be used to detect chemical warfare agents and hazardous chemicals. Sarin is a neurotoxic chemical agent. When studying its structure, chemical properties and spectral properties, in order to ensure safety, simulants are often used in the experiment to substitute for testing, but there is no fair near-infrared simulant for sarin. This paper uses density functional theory (DFT), based on the Gaussian program package, and uses B3LYP/def2-SVP to optimize the ground state structure of the sarin molecule, and calculates the fine structure of the sarin molecule and the fundamental frequency vibration mode of the molecule. The generalized second-order perturbation theory (GVPT2) is introduced to establish a theoretical model for simulating the near-infrared spectrum of biochemical poisons, obtaining the near-infrared vibration peaks and main vibration modes, and the near-infrared spectrum drawn from the vibrations of overtones and combination bands. Analyze the hydrogen-containing groups of sarin in the near-infrared region, use this method to identify its characteristic peaks, obtain three characteristic peaks of sarin molecules at 1 150, 1 362 and 1 500 nm and analyze their vibration modes. Among them, the position at 1 150 nm is produced by the contribution of multiple overtones and combination bands vibration. 1 362 nm is a wide absorption vibration region, mainly caused by the combination bands of atoms connected to C atoms in the molecule and other non-C, H atoms. The near-infrared vibration peak at 1 500 nm is mainly caused by the C8 Related vibration mode contribution. In this paper, the theoretical model of Sarin’s near-infrared spectroscopy is established through density functional theory, and the feasibility of the theoretical model is verified through experiments, which provides theoretical support for finding its near-infrared spectroscopy simulation agent.