During horizontal lapped deposition with solidification of an aluminum molten droplet onto an aluminum substrate, the effects of the surface morphology and interior quality of the specimens under different process parameters were studied in this paper. By research of the single metal droplet deposition behavior, the horizontal lapped deposition of numerical model was established, and the evolution of morphology and temperature of one, two, three and four molten droplets horizontal lapped deposition impacting a substrate surface at different time respectively and multiple droplets successively deposition experiments under the different simulation parameters were carried out. In order to confirm the numerical simulations and experimental verification, the comparison between numerical simulations and experiments shows a good agreement. The optimal parameters are obtained. This investigation is essential to implement effective process control in metal micro-droplet deposition manufacture and it provides technical support and reference for the complex metal parts of molten droplets horizontal lapped deposition process.