The invention belongs to the technical field of power system automatic monitoring and discloses a power supplying voltage automatic acquisition system deployed on two levels in a centralized mode and a method thereof. By the adoption of a three-layer systematic frame of a device layer, an access layer and a main station layer, main monitoring stations are deployed on the two levels of a provincial level electric power company and a headquarter in the centralized mode to achieve real-time acquisition and transmission, uniform storage and business application of voltage data. The voltage data already in a business information system including dispatching, marketing and the like can be fully utilized, and the power supplying voltage automatic acquisition system can ensure stability of a system kernel while being adapted to data access of a heterogeneous system, so that communication and information resources are saved. A safety chip is arranged in a device, the safety chip is matched with a province-level safety access platform in use, strategies of identity authentication, encryption transmission, access control and the like are adopted, and the voltage data can safely have access to an electric power information intranet.