The invention discloses a power grid monitoring information basic event generating and updating method. The power grid monitoring information basic event generating and updating method comprises the steps: collecting power grid monitoring information, and recognizing a signal event corresponding to the power grid monitoring information according to a predefined signal event rule base; and according to the equipment to which the power grid monitoring information belongs, merging the signal events according to the same equipment in the same interval to generate a basic event. According to the basic event generation method provided by the invention, event identification is carried out on the power grid alarm isolated signals, and merging is carried out according to the equipment, so that thenumber of monitoring alarms is greatly reduced, especially the situation of frequent signal occurrence is greatly reduced, and the monitoring operation monitoring efficiency is effectively improved. According to the basic event updating method provided by the invention, through an updating mechanism of the basic event, a regulator can sense the change condition of the equipment state and assist equipment state trend analysis.