Processing technology of waterproof, moisture-proof and mildew-proof material for old building wall

The invention relates to the technical field of building materials, and provides a processing technology of a waterproof, moisture-proof and mildew-proof material for an old building wall. The processing technology comprises the following steps: a concrete base surface is manufactured; a waterproof layer is arranged on the surface of the concrete base surface; a waterproof layer is manufactured by using a waterproof agent; the waterproof agent is a water-based permeable crystallization type waterproof agent; a damp-proof layer is arranged on the waterproof layer; and a mildew-proof layer is arranged on the damp-proof layer. Therefore, aiming at the problems that an existing waterproof structure is unstable and not durable, and an old basement is prone to leakage, moisture and mildew, the waterproof layer, the damp-proof layer and the mildew-proof layer are arranged on the concrete base surface from the principle, so that outdoor vaporous water and liquid water are prevented from permeating; and the problem of