It is very difficult to laser cladding copper-tungsten composite coating on pure copper surface, and the Marangoni effect plays an important role in the molten pool formed by laser cladding, so it is necessary to study the influence of the laser power scanning speed and the change of spot radius on the Marangoni effect. Therefore, in this study, COMSOL software was used to conduct numerical simulation of copper-tungsten composite coating on the surface of pure copper, and combined with convective heat transfer, the changes of Marangoni effect under different laser power, scanning speed and spot radius were analyzed. The results show that the smaller the cladding power, scanning speed and spot radius, the larger the Marangoni effect is. Therefore, the appropriate increase of laser power scanning speed and spot radius will weaken the Marangoni effect, so as to provide guidance for obtaining more excellent copper -tungsten composite cladding layer.