The invention discloses an embedded 
firmware online 
upgrade method. The method comprises the steps that a remote 
client issues an update file to an embedded terminal through an 
upgrade port; an 
upgrade service program of the embedded terminal runs at the background, the upgrade port is monitored, and the update file is transmitted abiding by a protocol accepted by both parties once a demand is made; after the embedded terminal judges that the update file is transmitted successfully and is intact, the update file is saved into an update 
directory, and then a 
system is rebooted; after the embedded terminal is started to enter the 
system, a start detection script of the embedded terminal judges whether the update file is under the update 
directory, and if yes, the update file is copied to a corresponding application program 
directory and a driving directory; and after 
copying is completed, the original file under the update directory is deleted, a driving module, a main application program and the upgrade service program are loaded, and upgrade is completed. Through the method, upgrade of the application program and the driving module can be realized quickly and effectively.