On the basis of the analysis about present water resource situation in China ,the disadvantage of the forrnmula of flow loss and water using coefficient on anti－seep channel which have been applying in channel dernsign and water saving irrigation administration will be indicated in the paper. The characteristics of that the rnloss of conveying water is changeable with the flow changing have been take into account in the new formula.rnThe formula is validated by the example of middle permeable channel (A ＝ 1.90,m ＝ 0.40). The calculate rernsult is more precision. Also some formula has been given,they can be referred to the worker of the irrigation rnadministration.