An online upgrade method of remote embedded firmware comprises an APP program and a Bootload program. The APP program comprises the steps: S1, setting an offset interrupt vector table; S2, initializing a clock and a peripheral; S3, establishing a communication connection with that server; S4, receiving and identifying the instruction sent by the server requesting to upgrade the firmware; S5, judging whether that upgrade is agree or not; S6, marking that upgrade flag bit; S7, sending a response signal. The Bootload program comprises the following steps: S8, initializing the offset of the APP program, and setting the offset interrupt vector table to zero; S9, judging whether the upgrade flag bit is a specific flag; S10, receiving and identifying a data packet containing firmware data sent bythe server; S11, judging whether that firmware data is correct; S12, programming firmware data into a flash memory; S13, sending the firmware upgrade feedback signal to the server. In this way, the embedded firmware can be updated remotely safely and efficiently.