The invention discloses a power terminal communication access network topology dependent failure section determination method. In the same network topology, each optical network unit (ONU) is enabled to establish "hand-in-hand" type connection with fiber terminal devices OLT at two sides and a fiber terminal device OLT' through two PON ports, fibers connected in two directions are different fiber cores of the same optical cable, and once the optical cable for networking is interrupted, each ONU on a "hand-in-hand" link generates an optical signal loss alarm. According to the process and steps, a fault section of a power terminal communication access network can be rapidly determined, and the fault inspection and processing efficiency is improved.