The invention discloses a patterned porous polymer coating. A preparation method mainly comprises the following steps: (1) obtaining modified polyanion with photocrosslinking activity through chemicalmodification; (2) assembling polycation and the modified polyanion with photocrosslinking activity in layer-by-layer to obtain a coating material which is rough in the surface and loose in the internal structure; (3) preparing a smooth and compact coating by placing the coating material in a humid environment or in contact with water; (4) subjecting the coating to region selective ultraviolet cross-linking through a photomask engraved with a certain pattern; (5) placing the coating in a hydrochloric acid solution, and realizing regional pore-forming, so as to obtain the patterned porous polymer coating. The method has the characteristics of being environment-friendly, simple to operate and accurate and controllable in pore-forming area, and can be used for preparing the selective pore-forming coatings of the regions with different shapes and different sizes, furthermore area loading of the functional molecules such as dye, drug molecules and quantum dots can be achieved.