Using the data of Chinas 30 provinces from the year 2004—2014 to make M L TFP decomposed as technological progress and efficiency improvement， as well as the panel threshold return， we have found that the evolution of TFP has a significant influence on export growth. Under the threshold of GDP per capita， efficiency improvement shows a more important role， while the technology progressing becomes the other significant one once the threshold is broken. And the neglect of synergism of them may be one of most important reasons for todays export slow down. At the same time， demographic dividend is gradually fading away， the function of average years of education and FDI diminishes， while the institutional dividend like the input of social security enhances significantly. With the gradual elimination of demographic dividend， the elements for export growing will shift to new comparative advantages like human dividend and institutional dividend. According to the huge regional economic disparities， focus on the right path for the evolution of TFP， building and upgrading the new comparative advantages， may be the key to achieving the sustainable growth in exports.