In order to study the effect of machining error on the sound absorption properties of micro perforated panel (MPP) absorber, the theoretical model of MPP on considering the effect of machining error is built based on the MPP theory and electro acoustical equivalent circuit principle. The pore size distributions submit to the hypothesis of the normal distribution and average distribution are numerical discussed. Compared with the uniform diameter holes, the sound absorption peak is slightly lower and sound absorption bandwidth is slightly narrower when there are processing errors.