The invention relates to the field of solar spectrum selective absorbing coatings, and in particular to a solar spectrum selective absorbing coating with a continuous and adjustable absorbing edge and a preparation method of the solar spectrum selective absorbing coating with the continuous and adjustable absorbing edge. The preparation method of the solar spectrum selective absorbing coating with the continuous and adjustable absorbing edge includes the following steps that a substrate layer is cleaned; an infrared reflecting layer is prepared on the substrate layer through a film coating method; an absorbing layer is prepared on the in infrared reflecting layer through a film coating method; a reflection reduction layer is prepared on the absorbing layer through a film coating method; and the absorbing layer sequentially comprises a metal sub-layer, a semiconductor germanium sub-layer and a metal-nitride-oxide sub-layer from bottom to top, and the metal sub-layer, the semiconductor germanium sub-layer and the metal-nitride-oxide sub-layer are all sequentially prepared through a film coating method. The solar spectrum selective absorbing coating with the continuous and adjustable absorbing edge is prepared through the preparation method. The coating preparation technology is simple, the condition requirement needed by a coating device is low, and the preparation method is suitable for large-scale low-cost production.