Based on photoisomerizations and photoinduced alignments of an amorphous copolymer containing azobenzene groups,the writing process of the surface microstructures was studied. Some pattern structures were written on the sample surface by irradiation with two coherent laser beams. The forming mechanism and the polarization selectivity of the microstructure on the polymer surface was discussed by contrasting the phenomenons of azobenzene and di-azobenzene during the experiment.