The invention relates to a whole-course us-level-precision wireless ethernet synchronization apparatus of an intelligent transformer station and method thereof. The apparatus comprises a chip DP83640, an FPGA, and a constant-temperature crystal oscillator. Therefore, clock synchronization of different devices in a wireless Ethernet network without the IEEE1588 capability can be realized; and the apparatus and the method can be applied to development of various distributed electrical capacity quantity simulation and detection devices in a power system widely.