Furnace lining structure of vertical pit-type gas carburizing furnace

The utility model provides a furnace lining structure of a vertical pit-type gas carburizing furnace. The furnace lining structure comprises a furnace body lining, a furnace bottom lining and a furnace cover lining, wherein the furnace body lining is of a composite structure, the composite structure is implemented through taking a refractory brick and an alumina silicate fibrofelt I as the inner layer and taking aluminum silicate fiber cotton as the outer layer, the furnace bottom lining comprises a knotting material, an impervious carbon brick, a high-alumina brick and a clay brick which are sequentially arranged from top to bottom, the furnace cover lining is of a heat preservation bag structure or a folding block knotting structure, and the heat preservation bag structure adopts a heat preservation bag made from heat-resisting materials and an alumina silicate fibrofelt II for filling the heat preservation bag. The furnace lining structure of the vertical pit-type gas carburizing furnace can well seal a he