Provided are a method of assisting monitoring alarm method and a medical external equipment and a medical host equipment using the method. A technical scheme thereof comprises connecting the medical external equipment with the medical host equipment through an interface, wherein the medical external equipment forms a plug-and-play external alarm equipment. The medical host equipment performs self-check, and sends an alarm information to an auxiliary alarm device of the medical external equipment and generates a corresponding alarm when an alarm device in the medical host equipment works abnormally, thereby reducing a risk to the medical host equipment in the situation that the alarm device in the medical host equipment is in failure.