The invention discloses a corner upright post, two-side oblique beam and drainage channel cross beam connecting structure of a sunlight house. The connecting structure mainly comprises a corner upright post, wherein the upper end part of the corner upright post is respectively connected with the connecting end parts of a two-side oblique beam and a drainage channel cross beam, which intersect and are in contact; the upper end part of the corner upright post is provided with mounting surfaces which are respectively connected with the connecting end parts of the two-side oblique beam and the drainage channel cross beam; a lower circular hole is formed in the mounting surface which is in contact with the connecting end part of the two-side oblique beam; an upper circular hole which aligns to the lower circular hole is correspondingly formed in the connecting end part of the two-side oblique beam; a metal screw rod is screwed in the upper circular hole and the lower circular hole to connect the two-side oblique beam with the corner upright beam; a dovetail joint female groove is formed in the side face of the connecting end of the two-side oblique beam; a dovetail joint male head is arranged on the connecting end part of the drainage channel cross beam; the drainage channel cross beam is connected with the two-side oblique beam by the insertion of the dovetail joint male head in the dovetail joint female groove. The corner upright post, two-side oblique beam and drainage channel cross beam connecting structure of the sunlight house has the characteristics that the processing precision and the production efficiency in a factory are improved, the installation quality and process at a construction field are improved, the indoor decoration effect of the aluminum-clad wood sunlight house is greatly promoted, and the like.