Diagnosis monitoring method and system based on tree topology

The invention discloses a diagnosis monitoring method and system based on tree topology. The method comprises the steps that a controller generates an I/O module diagnosis information obtaining task and an I/O network diagnosis information structure according to a configuration file; the diagnosis information acquisition task period acquires diagnosis information and writes the diagnosis information into the I/O network diagnosis information structure; the controller summarizes and judges the state of each element of the network step by step from bottom to top according to the I/O module diagnosis information, the I/O network diagnosis information and the tree-shaped I/O network topological relation; and the configuration software obtains the states of the elements of the I/O network topology after judgment and summarization from the controller and displays the states in a graphical mode. According to the technical scheme, the abnormality of each level of element of the I/O network can be visually displayed,