The invention discloses a method for preparing Pu'er raw tea through 39 procedures in the technical field of preparation methods of Pu'er raw tea, the quality of ancient tree tea is comprehensively screened, fresh leaves which have certain and uniform bud-leaf-stem proportion, complete buds and leaves, no sandwiched leaves or single leaves, basically consistent size and length and no impurities are adopted for picking fresh leaves, the high quality of the raw materials is ensured, then the fresh leaves are placed in a green leaf storage frame, the freshness of the fresh leaves is kept, the thickness of the stacked fresh leaves during spreading and airing is based on the fact that the bottom layers of the fresh leaves do not generate heat, green grass gas is volatilized, conversion of components contained in the fresh leaves is promoted, full-manual fixation is conducted, spreading and airing are conducted slightly after fixation, so that the temperature of the leaves is reduced, then sunlight drying and sunning treatment is conducted, the whole drying area must reach a pollution-free standard, so that the quality of raw tea raw material selection can be guaranteed, the process precision of raw tea preparation can be effectively guaranteed, the quality of raw tea preparation is improved, the yield of raw tea is effectively improved, and the quality of the Pu'er raw tea can be improved.