The invention provides a realization method of replacing a serial port by a network port in an embedded system. The method comprises following steps: setting an independent network port; replacing the serial port by the independent network port directly connected to a processor; booting BOOT to load an independent network port drive preferentially; compiling the data sending/receiving interface of the independent network port; and sending/receiving UDP broadcast messages through the independent network port so as to replace the data transmission of the serial port. According to the method of the invention, the operation process of the embedded system is controlled through the network port under a condition that a serial port cable is not connected; therefore, software debugging and fault detection and positioning can be carried out conveniently in the using processes of a majority of portable computers with the network ports without the serial ports; the integral operation and control performance of the embedded system application devices can be promoted greatly; the user experience is optimized; and the maintenance cost is reduced.