Abstract: Objective The aim is to explore influence of key process parameters such as traverse speed and feed speed on forming quality of Mg-Gd-Y-Zr rare-earth magnesium alloy during additive friction stir deposition (AFSD), and to establish a matching strategy for process parameters. Methods Single-pass single-layer deposition experiments were conducted. With a fixed rotational speed of 200 r/min, matching relationship between traverse speed and feed speed was regulated. Multi-dimensional evaluations were performed through surface morphology analysis, cross section observation, roughness measurement, and material filling rate calculation. Results Roughness remained relatively stable within the range of 60～100 mm/min traverse speed. The feed speed and traverse speed dominated geometric dimensions and filling rate of deposition layer, and material shortage defects occurred when feed speed was lower than 0.7 mm/s. Conclusion A quantitative matching model feed speed-traverse speed-deposition layer volume was established, and the optimal process window was determined with traverse speed of 80～100 mm/min and feed speed of 1.0～1.1 mm/s.