Abstract: The reasonable hole bottom fluid pressure drop control of coalbed methane(CBM) well was important to make the well get thehigh and stable production. A new method to optimize the reasonable hole bottom fluid pressure drop control had been put forward in thispaper. Based on the analysis of the characteristics of high prod uction wells' hole bottom fluid pressure drop in Shizhuang South Block,thispaper viewed those factors that influenced the hole bottom fluid pressure drop system as a fuzzy set,decided the weight of every factor andused subordinate function to optimize the production of CBM wells,which meant adjusting the hole bottom fluid pressure drop syst em forthe low-production CBM wells or making the reasonable and scientific scheme of hole bottom fluid pressure drop for those wells that hadnot been put into service. Th is method was verified through some high-production Well L-1 and the hole bottom fluid pressure drop systemdetermined by this method coincided well with the actual syst em of Area 7 and the errors of the influencing factors were all less than 20%. This example proved that Fuzzy Mathemactical Method could be used to optimize the hole bott om fluid pressure drop system.