The invention discloses a hot-water furnace with corrosion resistant flue pipes. An internal furnace consisting of a furnace internal flue pipe, a smoke gathering chamber, a heating pipe and a combustion chamber is arranged in the center of a furnace body; and a furnace external flue pipe is welded on the upper part of the furnace internal flue pipe. The furnace external flue pipe and the furnaceinternal flue pipe are made of the same material and have the same inner diameter, and the wall thickness of the furnace internal flue pipe is two times of that of the furnace external flue pipe; thefront, the back, the left and the right on the middle part of the furnace body are provided with a cleaning hole respectively and cleaning hole gaskets and cleaning hole covers are fixed on the cleaning holes by a plurality of bolts; the left and the right on the lower part of the furnace body are provided with a dirt discharge hole respectively; the lower edge of each dirt discharge hole is levelwith the inner surface of the furnace bottom; and dirt discharge hole gaskets and dirt discharge hole covers are fixed on the dirt discharge holes by a plurality of bolts. The hot-water furnace withthe corrosion resistant flue pipes has the advantages that: due to increase of the wall thickness of the furnace internal flue pipe, the furnace improves the corrosion resistance and is prevented frombeing corroded too early. The cleaning holes in a plurality of directions provide sufficient light in dirt removing process, and convenient operation and thorough cleaning are realized; and dirt is discharged from the two dirt discharge holes smoothly.