The software used tosimulate temperature and velocity fields in laser surface remelting process is developedon the basis of PHOENICS code. Computational methods ,which include a fixed-grid andgeneral source term based on dealing with melting and solidification, are employed.Momentum and energy changes caused by moving heat source are taken as additional sourcesin controled-equations, and the equations are discretived and solved using acontrol-volume-based method. By using the software, numerical calculationon heat transfer,phase change and fluid flow in laser remelting process of an aluminum alloy speciman arecarried out.