The invention discloses a bus voltage checking method, and relates to a method for monitoring whether the bus voltage of a power grid exceeds limit. According a traditional bus voltage monitoring method, each bus is respectively monitored, when voltages of parallel buses are changed synchronously and exceed the limit, a plurality of repetitive invalid alarms are generated, and the monitoring and operation of a dispatcher are interfered with. The bus voltage checking method comprises the following steps: taking parallel buses which are in the same station and have the same voltage class as a virtual checking bus; obtaining a line voltage value of the bus; when the line voltage of the bus is smaller than an outage set value, considering that the bus is stopped, and filtering out the stopped bus; after the stopped bus is filtered out, checking a remaining bus; when the line voltage of the bus is positioned between the set maximum value and the set minimum value, considering the line voltage of the bus to be normal, otherwise, considering the line voltage of the bus to exceed the limit, and giving out only one alarm when the bus voltage of the parallel buses which are in the same station and have the same voltage class exceeds the limit. According to the technical scheme, interference caused by invalid alarms is reduced, and an effective technological support is provided for operation monitoring personnel to better monitor the bust voltage.