Abstract: The digital radiography image shows contrast by the difference between pixel values created in accordance with absorbance difference of transmitted X-ray to object. The purpose of this study is to propose the need of standardization of pixel value representation in digital radiography image. The unprocessed images and processed images are obtained through various types of X-ray equipment and analyzed pixel values. As the result of pixel value analysis, the unprocessed images represented pixel values in accordance with X-ray signal intensity while processed images represented pixel values in accordance with gray scale. In order to understand the relationship between radiation dose and pixel value in digital radiography image, the pixel value representation which reflects X-ray signal intensity is necessary.