Abstract: Only more than twenty years has coalbed gas,which mainly consists of methane and also called as coalbed methane (CBM),been recognized as an emerging unconventional natural gas resource.Cualbed gas is generated as a result of coalification process and stored in coal bed itself.Based mainly on the analyses of literature contributed to the branch science of geology before 1986,a brief review on the expositional falsehood for the phrase "coalbed methane" explained by the author of 《Dictionary of Geology》is given in this paper,and point out that,the reader was not given any correct and useful information by the phrase author;especially,a negative estimation of its industrial and commercial value had impeded the progress in research,exploration and development of coalbed methane in China.So that,the explanation of the phrase "coalbed methane" is in need of revision when republishing the dictionary.