Abstract: Oil and gas losses in oil refineries generally make up 1 ‰-4 ‰ of the total prcessed which are too considerable to be negligible.In order to provide base for preventing and reducing the handling losses, it is necessary to work out a formula more approximate to reality.Technical personel in Lan Zhou Refinery have done a great contribution to this by working out a series of formulas for calculation of tank evaporation loss, receiving and delivery loss, loading loss, blending evaporation loss, dewatering loss in tanks, purging loss, pump displacement loss, etc, with a result true to the reality in the refinery.They are presented here for the engineers concerned to take for reference.