Formwork system of inclined concrete structure with opening and construction method of formwork system

The invention discloses a formwork system of an inclined concrete structure with an opening and a construction method of the formwork system. The formwork system comprises an outer inclined formwork, an inner inclined formwork parallel to the outer inclined formwork and a side formwork connected between the outer inclined formwork and the inner inclined formwork. The inclined supporting assembly is used for supporting the outer inclined formwork according to the designed inclined angle of a concrete structure, the inclined supporting assembly comprises a vertically-erected scaffold and a plurality of inclined struts which are connected into the scaffold at intervals in a penetrating and inserting mode, and the top ends of the inclined struts are all located on the same inclined plane; the inclination angle of the inclined plane is the same as the designed inclination angle of the concrete structure; the opening templates are connected to the inner periphery of the opening in a surrounding manner; and the inne