A X-ray imaging flat-response low-pass filter technology based on grazing incidence micro-cylinder mirror arrays is proposed. According to the X-ray optical theory, the principle of flat-response low-pass filter based on micro-cylinder mirror arrays is introduced and the computational method of the element transmission spectrum is analyzed. A micro-cylinder array sample is fabricated on the substrate of polyimide by electron-beam lithography, with 200 nm column diameter, 1.3 μm height and 0.393 duty ratio. According to the theoretical calculation, when the glancing angle is 2°, the end-energy is 1250 eV and the unevenness is 5.7%. Transmission of this array is calibrated on 4B7B soft X ray beam line station of Beijing synchrotron radiation facility from several grazing-incidence angles, using a three dimensional precision angle institution of which the angular precision is better than 0.1°. The initial calibration result is attained. Calibration result shows that for all the grazing-incidence angles, the transmission presents on declining curve over 1 keV, and the downturn energy decreases as the angle increases. It demonstrates that the increase of glancing angle has an restraint effect on the high-energy X-ray. Because of the electron-beam lithography limits, the depth to width, side wall perpendicularity, side wall roughness and other parameters of the sample can not reach the theory requirement, thus the calibration result has an certain difference from the theoretical calculation.