A sub-pixel rendering method for a Delta RGBW panel and a Delta RGBW panel with sub-pixel rendering function are provided. The sub-pixel rendering method for a Delta RGBW panel is disclosed. The method comprises: utilizing a controller to classify all sub-pixels of the Delta RGBW panel into a first type of sub-pixels, a second type of sub-pixels, and a third type of sub-pixels; rendering the first type of sub-pixels by a left pixel, a current pixel, and a right pixel; rendering the second type of sub-pixels by a current pixel and a right pixel; and rendering the third type of sub-pixels by a left pixel and a current pixel.