To clarify the transformation pathway of adenosine during water extraction of Chinese Cordyceps.A HPLC method for simultaneous determination of seven nucleosides(adenosine triphosphate，adenosine diphosphate，adenosine monophosphate，adenosine，inosine，hypoxanthine and adenine)in Chinese Cordyceps was developed.By comparing the change of nucleosides’ contents before and after adding of standards，it was found that adenylate(adenosine triphosphate / adenosine diphosphate / adenosine monophosphate)can be transformed into adenosine，and adenosine can be transformed into inosine at room temperature water extraction condition.