The invention provides a method and a system used for determining clock abnormity of an electricity utilization information acquisition system. The method comprises steps that status word data items and clock battery voltage data items of equipment are acquired regularly; according to the received status word data item of the equipment, the clock chip undervoltage alarming conditions of the equipment are determined, and the proportion of the clocks having undervoltage alarming functions in all of the clocks is calculated; according to the received clock battery voltage data items, clock battery voltage data of each factory batch is determined, and the clock battery voltage data smaller than a normal operation voltage is selected from the clock battery voltage data of each factory batch according to a first proportion from small to large, and the equipment corresponding to the selected clock battery voltage data is determined as clock battery undervoltage equipment; effective power cut information is acquired daily, and the clock battery undervoltage equipment is combined with the equipment corresponding to the effective power cut information, and when superposition exists in the abovementioned two equipment, the clock of the superposed equipment is abnormal.