Objective To introduce direct digital dual energy subtraction radiography and explore it's clinical application.Methods The cases acquired separately by direct digital conventional radiography and direct digital dual energy subtraction radiography were compared.Results The detection rate,sensitivity and accuracy of calcifications in lungs,pulmonary nodules,stones in urinary system,calcifications of coronary artery and cardiovalvular were improved by using direct digital dual energy subtraction radiography.Conclusion Direct digital dual energy subtraction radiography is more valuable in clinical applications.