Abstract: To investigate possible influences of phosphine fumigation in tobacco aging warehouse on ambient air quality around the warehouse, the phosphine concentration in the samples of ambient air collected at four stages of the treatment, i.e., pre-treatment, dosing, airtight treatment and ventilation were measured according to the analytical method described in GBZ/T 160.30-2004. The results indicated that:1) The concentrations of phosphine in the ambient air around the warehouse at the four stages were undetectable-0.13 (pre-treatment), undetectable-0.18 (dosing), undetectable-0.12 (airtight) and undetectable-0.67(ventilation) mg/m³, respectively. 2) The effect of phosphine fumigation on the ambient air was the greatest at ventilation stage, the peak concentration of phosphine in ambient air reached 0.67 mg/m³ in 2008 when the purification technique for phosphine was immature and had since improved. The effect on surrounding environment can be effectively reduced by taking the ventilation stage as the key prevention and controlling period.