Based on the embedded-atom method, molecular dynamics simulations have been performed on solidification processes of liquid metal Fe by using crystal-liquid configuration method at two different cooling rates.In this way,it simulates the process that metal Fe is treated by laser beam. By the analyses of average atomic energy, pair correlation function, common neighbor analysis and atomic configuration, it is studied that the evolution process of system and the structure characteristic of final state.It is found that the transfer velocities of crystal-liquid interface are 1.74m/(s.K) and 0.89m/(s.K) at cooling rates of 2K/ps and 5K/ps. In the final state,owing to the disordered atoms, some atoms’ engrey are higher than the original state at the interface.And there are some high-energy nanoperticles in the original liquid part.It provides the microstructure foundation to study the mechanical property of metal Fe treated by laser beam.