The aims to improve the molding quality and printing precision of single melt channel and single layer through research and experimental exploration and find the best process path to reduce spheroidization and splash defects. The single melt channel was formed by printing with different laser power, point spacing and line spacing. According to the single melt channel forming quality, the range of forming process parameters with better surface quality was selected, and the single layer forming experiment was carried out. The spheroidization and splashing defects were studied and analyzed in the single melt channel and single layer forming tests, and their generation mechanism and influence on surface quality were discussed. The single layer test was further carried out and the reasonable range of process parameters was found to improve the surface quality of the single layer. The surface spheroidization and splash defects have great influence on the forming quality and accuracy of single melt channel and single layer, and the energy density is the main reason for the defects. Proper energy density can improve the surface quality. When the linear energy density is 0.4~0.6 J/mm and the surface energy density is 4~6 J/mm2, the formed sample surface is relatively flat, and it’s good in quality and high in precision, the spheroidization and splash defects are significantly reduced. When the energy density is appropriate, the defects of spheroidization and splash are obviously reduced. The forming effect of single melt channel and single layer is good, and the flow is uniform and continuous. Speroidization and splash defects happens with some regularity, which can be avoided by optimal process parameters.