Abstract: The Triassic productive intervals of oil and gas in Tahe oil field belong to low-resistivity reservoirs.According to the study of logging,geological,testing and analytical data,it is considered that lithology,mineralization degree,pore structure,bound water content,conductive mineral,interstitial (colloform) structure,mudstone interbeds and mud performance are important factors directly affecting the formation of low-resistivity reservoirs. Also, the practical significance of studying and distinguishing low-resistivity reservoirs is suggested.