Abstract: Aiming at the requirements of high-performance rapid prototyping of lunar regolith, this study proposes a method of lunar regolith forming based on fused deposition modeling. Considering the requirements of the molding process and engineering constraints, the scheme design of the lunar regolith fused deposition modeling device was carried out. By establishing a simulation model of the coupling of computational fluid dynamics and heat transfer, the sedimentary flow and phase transition behavior in the process of lunar regolith formation are numerically simulated. The simulation results show that in the temperature range of 1223 ℃ to 1323 ℃, the molten lunar soil has good fluidity and constraints, which can realize continuous deposition molding, which verifies the feasibility of the method. When the movement rate of the forming platform is less than 6 mm/s, there is no significant change in the deposition line width, and the maximum value is 12.5 mm. As the movement rate increased, the line width showed a downward trend, reaching a minimum of 4 mm at 30 mm/s. The forming rate is determined by the line width and the movement rate of the forming platform, and the molding rate can reach a maximum of 1000mm3/s when the moving rate is 20 mm/s.