Abstract: Integral diffraction coefficient including high diffraction order is the basis of identification of X-ray line, study of X-ray crystal characteristy, X-ray line intensity quantitative measurement and X-ray monochromatic image diagnosis. On the automatic X-ray diffractometer (XRD), based on the stability and precision control of and 2 goniometer, special plane crystal holder was made. Bremsstrahlung and Cu K line were attenuated for 5 orders by 40 m-thick pure Nickel filter in 15 kV and 20 mA supply to X-ray Cu tube, X-ray source of Cu taget is to be Cu K monochromatic source, transmission coefficient of Nickel filter is the criterion of Cu K monochromatic source. For X-ray Pentaerythritol(002) crystal,integral diffraction coefficient of 1-3 order diffraction on Cu K energy were calibrated. The results show that integral diffraction coefficient of the 2nd order and the 3rd order is only 14.36% and 4.07%, the Cu K1 intensity ratio of the 2nd order and the 3rd order is only 7.7% and 1.3% compared with the 1st order diffraction. This kind of calibration is efficient and convenient on XRD in common laboratory.