System, apparatus, and method for extending network with power supply are disclosed. The apparatus includes a processing unit, a signal and power integration unit, a power supply unit, a transmission rate regulation unit, a display unit, and a symmetric transmission control unit. The signal and power integration unit integrates the electrical power with the data packages, so that the normal data transmission line can also transmit electrical power alone with signals to the electrical devices which are connected to the network extending apparatus. Therefore, the electrical devices do not need any extra power transmission line or independent power supply for obtaining the requisite power.