The invention discloses a connecting node structure of a chimney. The connecting node structure comprises an outer barrel, an inner barrel, a thermal insulating layer and a foundation ring, wherein the inner barrel is sleeved inside a smoke inlet end of the outer barrel; the thermal insulating layer is arranged between the inner barrel and the outer barrel; the foundation ring is arranged at the bottom end of the outer barrel; rainproof eaves and insulated support rings are respectively arranged at the upper ends and the lower ends inside the outer barrel and outside the inner barrel; the inner barrel is connected with a high-temperature smoke outlet of a heat station through a transition section. By adopting the connecting node structure, the inherent problems of high temperature stress, easy transfer of vibration, need of an extra support structure, and the like of the conventional connecting mode are solved; meanwhile, the self-supporting capacity of the large tonnage chimney is achieved; and the usage amount of steel for supporting the large tonnage chimney is saved.