The angles of reflection and transmission from interaction of electromagnetic waves with a relativistic underdense ionization front are investgated. First, according to a phase matching condition of electromagnetic wave on the stationary boundary surface, we find the refelection and transimission angles in the front system with a static ionization front. Then using the transformations of wave vector and frequency we get the corresponding angles in the laboratory system in which the ionization front is moving at relativistic speed. The obtained results are discussed.