Premixer and gas wall-hanging stove

The utility model relates to the technical field of combustion heat exchange, in particular to a premixer and a gas wall-hanging stove. The premixer comprises a premixer main body, a reducing sleeve, a floater and an elastic piece, and a mixing cavity is formed in the premixer main body. The reducing sleeve is arranged at the outlet end of the premixer body in a sealed mode, and a containing cavity is formed in the reducing sleeve and used for being communicated with an inlet of a fan. A ventilation hole is formed in the first side wall, facing the mixing cavity, of the reducing sleeve, and the mixing cavity communicates with the ventilation hole. The floater is provided with a through hole and is movably arranged in the containing cavity through an elastic piece. The floater abuts against the first side wall through the elastic piece so that the mixing cavity can be communicated with the containing cavity through the through hole. And the floater can be separated from the first side wall, so that the ventila