Abstract: The molecular sieve adsorption dehydration two-tower process is adopted on dehydration unit of Natural Gas Purification Plant, Northwest Sichuan Gas District, PetroChina Southwest Oil & Gasfield Company, including one tower adsorption and one tower regeneration, and the two towers are switched to use. Under low load operation, the H₂S content in the product gas of the molecular sieve tower fluctuates periodically during regeneration, and there is a potential risk of exceeding the standard. After research and analysis, the optimized adjustment scheme was made. By prolonging the switching period of adsorption regeneration, reducing regeneration time and regeneration temperature, the H₂S mass concentration in product gas of the molecular sieve dehydration unit during regeneration was reduced to less than 10 mg/m³, and tended to be stable. The abnormal production problem was solved well.