Abstract: Using numerical calculation and experimental analysis methods, the deposition and spreading change of single metal droplet at different process parameters (deposition distance, scanning speed, melt temperature, substrate temperature, nozzle diameter, etc.). The validity of the current model was verified. Then, numerical models of single channel/multi-channel lap formations were established. Melt flow, spreading and coagulation mechanisms of the molten metal drop in the sedimentary formation were explored under small space and large temperature gradient. The results showed that when using the lap formation on a typical cross section, the influence law between primary characteristic factors, morphology and internal quality could be obtained by optimizing process parameters. This provides technical support and reference for the molten droplet depositing formation of the subsequent complex metal parts.