The invention discloses a Thiessen polygon grid-based power grid load visualization method, which comprises the following steps of: (1) obtaining power grid operation load and space information data based on historical operation data or real-time operation data of a plant station in combination with space position information; (2) generating a Thiessen polygon grid based on the geographic distribution of the plant stations; (3) traversing the Thiessen polygon mesh, and obtaining a plant station contained in the polygon mesh according to the topological nine-intersection model; (4) carrying outstatistical value processing on the plant and station load information in each grid, and carrying out statistics on a minimum value, a maximum value, a median value and an average value; (5) countingthe minimum value and the maximum value of the power grid load of the grid unit in the whole area; and (6) establishing color intervals corresponding to different numerical values using values of thecolor intervals corresponding to the median numbers obtained through statistics in each grid and coloring the polygonal grid. According to the invention, the power grid operation load geographic areadistribution condition can be effectively displayed. Therefore, the belonging power grid information can be considered, the grid area with higher load can be displayed with a clear boundary, and thegrid management is assisted.