This paper reports the design procedure and critical discussion about the relation between the input impedance and the bandwidth for obtaining the wide band, thin film microwave absorber in the X-band range. Two layered absorber composed of two kinds of non-dispersive dielectric materials were fablicated using the proposed design method, which was checked experimentally to be reasonable. The absorption properties of the microwave absorber of 0.248 cm in thickness and 2.2GH_z in bandwidth centered at 9.4 GH_z is demonsrated as an experimental example.