The invention relates to a melt collecting tank used for a continuous fluidized bed reactor. The collecting tank comprises at least two cutoff grooves and at least two honeycomb ducts, wherein the at least two cutoff grooves are formed in the side wall part of the reactor, and the at least two honeycomb ducts penetrate through the wall of the reactor; the cutoff grooves are groove bodies which surround the side wall part and are formed by beadings and the side wall part of the reactor, wherein the beadings are located on the side wall part of the reactor and protruded to a reaction chamber; the cutoff grooves surround at least part of the side wall part in the horizontal direction so as to collect melts flowing down along the side wall part. The melt collecting tank disclosed by the invention is arranged on the side wall part to collect high-temperature liquid matter adhering to the wall of the reactor, and the high-temperature liquid matter is led out of the reactor, therefore not only are materials effectively separated and recovered and are prevented from being mixed with solid residues but also the liquid melts are prevented from blocking entrance for the materials.