This invention relates to a method and a system for fault localization of communication equipment including: obtaining internal test imformation of changeable units at site of equipment, searching forall unit circuits correlated with test information based on the test information and associated matrix describing the communication equipment to further search for the test information associated with the unit circuit in the unit circuit set based on the unit circuit and the associated matrix to set up a localized sub-matrix by the searched unit circuit set and the test information set and judgeand register the unit circuits with abnormal working state and register the corresponding FRU, which associates test or alarming information with the FRU circuit unit to localize faulty FRU automatically to overcome the shortcoming of unabling localizing fault quickly.