In this paper, a new high accuracy numerical method for the thin-film problems ofmicron and submicron size ferromagnetic elements is proposed. For the computation ofstray field, we use the finite element method(FEM) by introducing a semi-discrete artificialboundary condition [1, 2]. In our numerical experiments about the domain pattes andtheir movement, we can see that the results are accordant to that of experiments and otheumerical methods. Our method are very convenient to deal with arbitrary shape of thinfilms such as a polygon with high accuracy.