The invention discloses an intelligent station bus secondary voltage monitoring method and device. The method comprises the steps of: obtaining a first digital bus secondary voltage in real time by abus merging unit, and accordingly determining whether the bus voltage value is abnormal; if so, converting an analog secondary voltage in a bus bar control cabinet by a second AD conversion module andoutputting a digital second digital bus secondary voltage; comparing the first digital bus secondary voltage with the second digital bus secondary voltage; if the first digital bus secondary voltageis inconsistent with the second digital bus secondary voltage and the second digital bus secondary voltage is normal, determining that the fault is a bus merging unit fault; and if the first digital bus secondary voltage is consistent with the second digital bus secondary voltage, determining that the fault is a non- bus merging unit fault. The monitoring device is applicable to the intelligent station bus secondary voltage monitoring method. The method can determine the fault location and components of the measured bus secondary voltage anomaly. The device has a simple structure, can accurately monitor the bus secondary voltage by simply operating a few buttons, and is simple and convenient.