The invention discloses a decorating and beautifying method for the outer surface of a thermal power plant chimney. The thermal power plant chimney comprises a conical long chimney body built on a concrete base layer. The decorating and beautifying method comprises the steps that a gradually-varied dark blue anti-corrosion coating layer is smeared on the outer surface of the whole chimney body, and fluorescent white dots implying stars are dotted on the dark blue surface; the dark blue anti-corrosion coating layer on the outer surface of the chimney body refers to blues with five depths from RAl 640-1 to RAl 640-5 in a RAL color card, and all colors are gradually varied and transitioned, so that soft connection among the colors is guaranteed; 8-24 high-pole type LED large-power projection lamps are arranged around the chimney body, and the light projection height is controlled to be below two thirds of the chimney; and meanwhile a circle of LED large-power wall washer lamp is arranged on the top of the chimney body so as to draw the top outline.