The invention discloses a heating assembly. The heating assembly comprises a shell, at least one heating component and at least one connection piece, wherein the heating component is arranged in the shell, the connection piece is arranged on an outer wall of the shell, the connection piece and the shell are assembled and fixed, the connection piece comprises a groove and a groove wall, the groove wall is arranged at a peripheral side of the groove, at least one part of the groove wall is outwards sunken, the heating assembly comprises at least one cavity, the cavity comprises a space between the groove wall and the outer wall of the shell, the connection piece comprises a first interface and a second interface, the first interface communicates with the cavity, the second interface communicates with the cavity, and the first interface communicates with the second interface through the cavity. The cavity is arranged between the connection piece and the shell and is used for a fluid to flow, the surface temperature of the shell is taken away by flowing of the fluid in the cavity, so that the temperature of the shell is relatively low; and since the connection piece and the shell are assembled and fixed, the replacement of the connection piece is facilitated, the service lifetime of the heating assembly is favorably prolonged, and meanwhile, the thermal efficiency of the whole heating system is improved.