The present application relates to a self-adaptive software background update method and device. The method includes: monitoring a TCP download request in a system, after the system starts up; filtering a download request of a network video and a download request of a system update software from the TCP download request, when the download request of the network video and the download request of the system update software exist simultaneously in the TCP download request; downloading and playing the network video under a TCP link according to the download request of the network video, and obtaining a data cache amount of the network video; starting up downloading the system update software according to the download request of the system update software; controlling a download rate of system update.