Objective To explore the effects of different processing parameters of mobile digital radiography (DR) on image quality of bedside chest radiography.Methods Post processing parameter on 150 cases bedside DR chest image like multi frequency laplasse transform (MLT),image processing (IP) were modified,and the optimization scheme of post-processing parameters were analyzed and summarized.The paired sample t test was used to compare the difference of the imaging quality score and optical density between the default parameter group and the post processing parameter optimization group through measure the optical density of lung related area.Results Brightness,contrast and the low density in dynamic range were the main factors affecting the quality of bedside chest radiography.After modifying and optimizing the post-processing parameters,the density value of the second intercostal area was 1.68±0.04,the density value of the hilum was 0.77±0.46,the density value of pulmonary peripheral (near chest wall 1 cm and overlap with a single rib) was 0.62± 0.06,the density value of cardiac shadow was 0.44 ± 0.04,the density value of subphrenic was 0.37 ± 0.04,the lung markings was clearly showed in the lateral field of lung and was visible in the spine and heart shadow area which meet the diagnostic requirement.The density value of those parts before modify were lower than the modify value which was more closer to the reference density value,and the difference had statistically significant.The image quality score of the postprocessing parameter optimization group was 3.53 ± 0.14,which was higher than 3.02 ± 0.23 of the default parameter group,and the difference had statistically significant.Conclusion The appropriate post-processing parameters is the key to guarantee the reasonable density of lung areas image quality and the optimization post-processing parameter can improve the image quality of bedside chest radiography by the mobile DR.