The invention relates to the technical field of engineering materials, particularly relates to measurement of material performances and application of the measurement, and discloses a method for evaluating coatability of an asphalt and an aggregate and application of the method, wherein a coatability index (CI) is used to evaluate the coatability performance of the asphalt and the aggregate in an asphalt mixture, the index is defined as the relative difference of the water absorption rate of a coarse aggregate and the water absorption rate of a coarse aggregate in a loose asphalt mixture, the coarse aggregate is the coarse aggregate in the aggregate with determined mineral aggregate gradation in the asphalt mixture at a certain mixing proportion, and the coarse aggregate in the loose asphalt mixture is a mixture prepared by evenly stirring the coarse aggregate with certain amount of asphalt binder and cooling to room temperature. The method quantitatively evaluates the coatability degree and the coatability performance of the asphalt binder and the aggregate, has the advantages of simple and convenient operation and small error, and can be used to guide to determine a suitable foaming condition when the mix proportion of a foamed asphalt warm mixing mixture is designed.