Abstract: Laser melting deposition technology can quickly manufacture high-performance parts with complex structures, but there is a phenomenon of unstable deposition size during the part forming process. An experiment was conducted to analyze the influence of key process parameters on the deposition size for the laser melting single-track multilayer deposition process. The results indicate that the deposition size in the same deposition layer tends to stabilize as a whole. Due to factors such as the thermal accumulation effect, the deposition size between different layers in the area close to the substrate fluctuates greatly, while the size fluctuation decreases after a certain number of layers are accumulated. The relationship between the laser power and scanning speed and the deposition width and height in the different deposition areas is further analyzed, and a multi-layer deposition size prediction model based on process parameters is established, and the prediction error of the model is within 5%. The study provides a foundation for the dimensional stability control and process parameter optimization of the subsequent laser melting deposition process.