With the rapid development of the power system, the performance of vacuum circuit breakers has also put forward higher requirements. The contact is one of the key factors to determine the performance of vacuum circuit breaker, and anti-welding is an important index to measure the performance of the contact. In this paper, the evolution of melt pool morphology of vacuum circuit breaker is studied based on hydrodynamic model. Through the multi-physics field simulation, a two-dimensional melt pool micro-model has been established, and the surface micro-morphology of the melt pool is analysed. Through the simulation and experiment, metallographic analysis of the surface of the welded metal material is also carried out. Comprehensive experiments and simulations can provide a more intuitive understanding of the microscopic morphology of the molten pool.