The present invention discloses a heat supply system pipeline scale removing agent, which comprises the following raw materials by weight: 3-7 parts of manganese sulfate, 4-8 parts of an acrylic acid copolymer, 0.5-1.5 parts of sodium stearate, 3-7 parts of a bactericide, 7-9 parts of a rust removing agent, 5-9 parts of a penetrating agent, 5-8 parts of a protein decomposing agent, and 3-6 parts of a scale inhibitor. According to the present invention, the heat supply system pipeline scale removing agent can effectively remove water scale existing in the pipeline for a long time, has advantages of strong scale removing and no secondary damage on the pipeline, can make the pipeline form the scale inhibition function, can delay the secondary formation of scale, can increase the service life of the pipeline, can ensure the smoothness of the pipeline, can effectively remove a variety of bacteria produced during the use process of the heat supply pipeline, and further has excellent comprehensive performance; the preparation method has characteristics of low material cost, easily available raw materials, and simple process; and the obtained product as the heat supply system pipeline scale removing agent has high practical value and good application prospects.