The invention discloses a device and a method for downloading firmware of an embedded Linux system. According to the principle of downloading from the simple to the complex, the most fundamental and simplest part is downloaded through a serial port, then the more complex part is downloaded, and finally, a user application program is downloaded. By adopting the device and the method provided by the invention, the firmware downloading for the embedded Linux system can be completed by a PC, thus a Flash memory is programmed through serial port and a high-speed serial interface, and the disposition of the whole system is completed. Compared with prior art, the invention has the advantages of high downloading speed, simple operation, low cost, and suitability for both R&D stage and mass production stage.