The invention relates to the technical field of environment monitoring, in particular to a rain shading device for an environment monitoring station building. The rain shading device for the environment monitoring station building includes a rain shading device body and hanging rods, wherein the rain shading device body is fixed to the outer end of a protective plate, and the hanging rods are fixed to the top of the station building; the top of each hanging rod is in a hook shape; the rain shading device body includes a collection bin, a cover plate and a rain shading umbrella, wherein the collection bin is a cavity cuboid with a top opening and is fixed to the outer end of the protective plate, the rain shading umbrella is arranged inside the collection bin and includes elastic umbrella ribs and umbrella cloth, the outer end of the umbrella cloth is fixedly connected with the elastic umbrella ribs, the upper ends of the elastic umbrella ribs are provided with sleeve rings, and the sleeve rings are connected with the upper ends of the elastic umbrella ribs through springs. When folded, the rain shading umbrella is small and easy to fold, and when unfolded, the rain shading umbrellais large and good in rain shading effect; by the adoption of the elastic umbrella ribs, deformation and bending of the rain shading umbrella can be achieved, the rain shading umbrella is easy to setup, the collection bin promotes the storage and collection of the folded rain shading umbrella, and after the rain shading umbrella is folded, the working environment of a sampling device cannot be influenced.