Abstract: In view of characteristics of tuff reservoirs,the electric response,resevoir space and type and development of reservior were studied;the development and distribution of fractures and their influential factors were analysed;and influence of fractures on reservoirs and producing formation was discussed.It showed that the play Ⅱ of intermediate tuff developed in wheathering zone of buried-hills of the eastern area possessed good fractures and reservoirs,where was the habitat of principle hydrocarbon accumulation.The fractures provided suitable reservoir space and passway for hydrocarbon migration,so oil and pools were formed.