Abstract: Light end products (gasoline etc.) release a great volume of vapor in the course of receiving and dispatching process, which will lead to a serious problem of oil loss from evaporation. The article puts forward a technique and application study on debasing vapor evaporation, illustrates and contrasts several schemes for theses purpose. The scheme debasing loss in actual oil tank farm and technique design for vapor gas gathering system are determinate by calculation and case analysis, the corresponding conclusion and proposal are obtained.