The invention discloses a power generation and transmission system reliability tracking algorithm based on maximum risk analysis, and the algorithm comprises the following steps of generating a similar fault element set, and setting a system risk threshold value; solving by applying a maximum risk analysis model; generating a solving result, and generating a new system state set; carrying out therisk apportionment, and updating the risk contribution degree of each system element; and judging whether the risk value of the similar fault set is higher than a set system risk threshold, outputtingthe risk contribution degree of each system element, and determining the weak link of the system. The method has the beneficial effects that the main fault events can be effectively identified from asystem state set, and the risk contribution of the element can be quickly quantified through reliability tracking under the influence of element load shedding in combination with a similar fault state reduction technology, so that the corresponding weak link is determined.