Abstract: X-ray linear attenuation coefficients have applications in choosing X-ray source, evaluating X-ray source penetration capability, investigating shielding performance of materials, etc.This work has been done to measure linear attenuation coefficients for Aluminum, Tungsten and Iron.Samples of different materials and different thicknesses were positioned between the X-ray source and the detector array and the central beam passed through the samples perpendicularly.The greyscale values of three channels in the detector array were read out with different materials and different thicknesses.The linear attenuation coefficients were calculated by plotting the log of the transmitted intensity against the varying in thickness.Compared with the results in NIST and another reference the linear attenuation coefficients obtained indicate that there is a good agreement between the experimental results and the results offered by the references.The proposed method can be adopted as an alternative method to measure the linear attenuation coefficients of materials.