The invention relates to a molding ring for production of a large-caliber thick-wall seamless steel pipe and a surfacing compound manufacturing method thereof. Hole walls of conical working sections at two sides of an inner hole of the molding ring respectively comprise a surfacing transition layer and surfacing layers. The surfacing compound manufacturing method comprises the following steps: machining grooves in the conical working sections at two sides of the inner hole of the molding ring, depositing a surfacing transition layer in each groove, successively depositing surfacing layers on the surfacing transition layer, and carrying out finish machining to the finished size. By using structural steel as the base material of the molding ring and depositing high Cr-Mn-Mo austenitic steel surfacing alloy electrodes with excellent high-temperature wear resistance to form the surfacing layers, the service life is prolonged by more than seven times compared with the traditional structural steel molding ring, and the surface quality of the pipe blank of the large-caliber thick-wall seamless steel pipe is also improved. Because the molding ring has a thick wall, stainless steel electrodes which do not need to be preheated are deposited to form the surfacing transition layer before depositing the surfacing layers with electrodes in order to avoid the danger that the deposited metal peels off in use due to the quench hardening of the structural steel base in a heat-affected zone in the surfacing process.