With the development of our country, the demand for new and clean energy is also increasing. In 2019, the state promulgated the Measures for Fair and Open Supervision of Oil and Gas Pipeline Network Facilities in which the requirements for establishing a natural gas energy measurement system were clarified. As an important measurement method of natural gas energy measurement, calorific value measurement has become the research focus. For calorific value measurement, infrared spectroscopy detection is a popular measurement method. The total calorific value of the gas is calculated by detecting the content of each component of the gas. The accuracy of infrared spectrum detection is high. Due to the characteristics of its absorption spectrum, the ambient temperature will affect it. According to the principle of infrared spectrum detection Lambert Beer law, the detection model of gas absorbance is established through analysis and calculation. By analyzing the detection model, the linear relationship between ambient temperature and spectral absorption was obtained, and the method to reduce the influence of temperature was analyzed by using the relationship. The feasibility of the method is verified by experiments. The control of ambient temperature and the selection of absorption spectrum based on temperature can greatly reduce the impact of temperature and improve the accuracy of infrared spectrum detection.