In order to realize the integral forming of tungsten carbide WC-12Co metal powder products, the selective laser melting (SLM) technology was used for the theoretical analysis and experimental verification of the single-pass melting pool forming of WC-12Co alloy powder. The results show that: Different combinations of laser scanning rate and power affect the continuity and morphology of the single pass molten pool. When the laser power is 340 W, the scanning rate is 600 mm/s, the scanning interval is 60 μm/pass, and the powder thickness is 40 μm/layer, the single pass molten pool morphology reaches the best state, presenting a stable and continuous “fishscale” morphology. The single layer cracks of the forming object are the least. In the process of single pass forming, W element aggregation occurs in the section of single pass melting pool, which is an important reason for the anisotropy of formed WC-Co block. This research result plays a decisive role in the forming of cemented carbide WC-12Co metal powder products.