Benefiting from the great achievements in Life Science， especially in the Neuroscience， Molecular Biology and Functional Brain Imaging， over the past 20 years， there has been substantial progress in revealing the genes， molecules， cells， and circuits that regulate physiologic and pathologic pain and in understanding neurobiological mechanisms of pain modulation. However， few of these advances have been translated into effective clinical therapeutic means or/and new and improved analgesics. Why， what factors resulted in the giant gap between the pain basic research and clinical diagnosis and treatment This paper reviews the history in pain theory development and the mechanisms of pain signal processing， and makes brief comments on the obstacles and challenges of translational research on pain.