We propose a polygon resizing algorithm with antialiasing filtering. Data represented by polygons and analog data are similar. So, filtering and resizing processor are complicated. For that processor, we need to find the intersection points of a segment on the polygon and filtering region. Computing time of an intersection checking step is proportional to the number of segments and filtering regions. This paper reduces the computing time of the intersection checking step using a normalized coordinate transform. Furthermore, we find the inside region of the polygon in the filtering. As a result, we show that the aliasing effect is reduced by the proposed filtering.