The invention discloses a method and a device for monitoring real-time operation information of intelligent substations. The monitoring method comprises the following steps: (1) application for transmitting a data block composed of operation information once is made to an access unit at regular intervals; (2) the data block is acquired, and transmission time of the data block is kept; (3) whether the kept time exceeds a time threshold is judged, and the time threshold is smaller than or equal to the time interval; (4) when the kept time exceeds the time threshold, the step (2) is stopped, the steps (1)-(3) are repeated, and whether the kept time exceeds the time threshold two or more successive times is judged; and (5) when the kept time exceeds the time threshold two or more successive times, subsequent operation information waiting to be applied is pre-processed, the operation information is averagely cut into data blocks including data of the time threshold, and the steps (1) and (2) are repeated. Through the method, original operation information of intelligent substations can be stably monitored at constant speed.