Lin XU graduated from Nankai University with a Master' s Degree in Economics. He was awarded the Humphrey Scholarship of the U.S. Government during his study at American University, and the Singapore Government Lee Kuan Yew Scholarship during his study at Lee Kuan Yew School of Public Policy at the National University of Singapore. He also studied at the Kennedy School of Government of Harvard University and graduated with the Master's Degree in Public Administration.

In 1989, he was recruited to the Forecast Division of the Long-Term Planning Department of the National Planning Commission. He once served as Director of the Department of Fiscal and Financial Affairs of NDRC, during which he participated in the preparation of several Five-Year Plans for China's economic and social development, regional development plans, national new urbanization plans and national industrial policies. He was also engaged in the formulation of major reforms in the fiscal and financial sectors as well as the development and regulation of capital markets, especially bond markets and private equity investments. He used to serve as Member of Issuance Examination Commission of China Securities Regulatory Commission for three terms and participated in the negotiations of China's accession to the WTO, responsible for the negotiations on industrial policies and industrial subsidies.