Abstract: The one port network which only contains resistors or controlled sources，not including independent source，can be divided into pure resistors circuit and controlled sources circuits. As to pure resistors circuit，we propose a method of“searching roads by marking points”. As to the circuit with controlled sources，it can be resolvedby the external excitation method and internal excitation method. External excitation method includes the traditional method of “calculating current by inputting voltage”and“calculating voltage by inputting current”. As to internal excitation method，we also propose a new method named“open-short”.

Key words: searching roads by marking points, external excitation method, internal excitation method