The invention discloses an aircraft noise optimization method of continuous descending approaching based on an ant colony algorithm. The method comprises steps of firstly selecting noise sensitive points and coarsely selecting a noise optimal CDA basic approaching program; then, based on a PBN approaching reference program, constructing a continuous descending approaching nominal flight track control module, and carrying out correction; then, determining constraints borne by an aircraft in a continuous descending process and dividing a noise optimization transition space and a noise optimization approaching space so as to obtain selectable four-dimensional CDA flight track searching libraries corresponding to different aircraft states; and finally, by taking the minimal noise of the aircrafts in the approaching process as a target, establishing an aircraft continuous descending approaching noise optimization model, and listing an optimal descending approaching flight rack corresponding to different types of aircrafts, different operation states and different weather conditions. According to the invention, based on aircraft performance, the initial state and the weather conditions, the flight tracks of the continuous descending approaching of the aircraft are dynamically adjusted and reference is provided for an environmental protection level of the aircraft at a descending stage in a terminal region.