The invention discloses a method for plotting a right-angled building in a high-resolution optical image. The method comprises the steps of taking the right-angled building as a plotting research object, defining the main direction of the building with minimum MBR, taking the plotting area and perimeter as evaluation criteria, fitting each linear boundary of the right-angled building in combination with a minimum out-souring rectangular constraint, judging the corner rule of each linear intersection by a direction decider, and connecting the intersections into a closed polygon according to the rule, thereby realizing plotting of the right-angled building. The method sufficiently considers the right-angled characteristic of the building, is not limited to the existing contour points when the right-angled points of the building are determined, but can derive new data points to express corners, thereby improving the extraction precision, and simultaneously solving the problems of low plotting precision, insufficient robustness and poor fitting optimization strategy of the right-angled building of the optical image in the existing method.