Objective To get the optimal technological parameters for Al-Cu alloy cladded coatings on AZ91D magnesium alloy prepared by laser cladding. Methods The three-dimensional temperature field model of laser cladding under the moving GUASS heat source was established with ANSYS software. Then, the dynamic simulation of temperature field for laser cladding was conducted under different technological parameters. And the technological parameters were optimized by contrasting the melting point of Al-Cu alloy and the welding pool temperature. Finally, the experimental verification was performed. Results The results showed that the temperature at the center of welding pool increased with the rise of power (P) while decreased with the rise of the speed (v) of heat source and the diameter(d) of facula. When the temperature was excessively high, the cladding layer was collapsed and with internal cracks. However, when the temperature was too low, the cladding layer was covered with large amount of metal particles, and there were internal inclusions. Conclusion Under the conditions of P=240 W, v=2. 5 mm/ s and d=0. 6 mm, the temperature at the center of welding pool was about 1100 ℃, and the temperature at the contact surface of cladding and substrate was 700 ℃ . The smooth and compact cladding layer cohesively combined with substrate was obtained by experiment with those technological parameters.