The clean utilization of low-concentration gas is of great significance to improving energy utilization efficiency, mitigating the greenhouse effect and achieving dual carbon goals. In this paper, using the principle of displacement chromatography, an adsorptionAdsorption separation method for recovering methane gas in low-concentration gasLow concentration gas (≤30%) was developed. Using 5A molecular sieve5A molecular sieve as an adsorbent, the molecular structure of 5A molecular sieve5A molecular sieve was characterized by X-ray diffraction spectrum, infrared spectrum, and scanning electron microscope. The change law of separation and enrichment of low-concentration gas under the conditions of different volumes, different concentrations, different carrier gasCarrier gas velocities, and different column diameter ratios was studied. The research results show that: when the feed gas concentration increases within a certain range (10–30%), methane can be enriched to 2–3 times the original (25–76%) in one step, and the recovery rate increases slightly and stabilizes. Around 30%. When the concentration of feed gas is constant (15%), the concentration of methane after purificationPurification increases with the volume of single treatment, up to 77%, while the recovery rate decreases. When the carrier gasCarrier gas flow rate increases within a certain range, the concentration after purificationPurification is stable at around 50%. The column diameter increases (0.6–3 cm), the methane enrichment rate decreases from 54 to 36%, and the single treatment volume doubles from 900 mL to 21 L. The results show that this method may be applicable to the purificationPurification of low-concentration gasLow concentration gas.