Abstract: To solve the problem of gasoline evaporation loss during storage, internal floating roof tank can be used to replace the fixing roof tank.However, there are some disadvantages for internal floating roof tank, such as seal deformation, measuring error area and low efficient utilization coefficient etc.in the pontoon structure.The"condensation+ adsorption device" technique is proposed to decrease the gasoline vapor loss in tank or tankfarm, which not only eliminates the potential safety hazard from the internal floating roof, but also improves the recovery rate of gasoline vapor.Furthermore, it can decrease the concentration of gasoline emissions and improve the utilization efficiency of tank and the usage rate of gasoline vapor recovery device.Hence it will reduce the operating costs of tankfarm.Besides, it has significant economic and social benefits.