Abstract: A new finite difference approach to single-phase Stefafl problems is presented by using fixed-time step and variable space interval method .In fixed and equal lime steps, by taking the positions of moving interfaces obtained from computation as the grid points, and the difference between them as the space steps, meshes can be generated in computational domains gradually and automatically, the temperature is calculated at these grid points and the positions of moving interfaces of the next lime step are obtained.

Key words: moving interface, fixed-tirne-Mfep and variable-spaoe-interval finile differene approach, Stefam problem