The invention relates to a self-diagnostic method for a digital video recorder. When in execution of self-diagnostic operation on the digital video recorder connected with a plurality of cameras used for monitoring, the invention can detect particular channels chosen by users or error of influencing signal of every channel; meanwhile the invention can be continuously connected with a decoder chip, a mux chip, a PCI bridge chip and other electronic elements. The invention only filters and resets the malfunctioned electronic elements which minimize the frequency of restarting a system in a long time. Therefore, the invention can stably maintain the monitoring function of the digital video recorder.