Abstract: High-speed railway, as one of the competitive innovative achievements in modern scientific technology, has been developing greatly. How to rationally analyze high-speed rail’s effect on regional development and make comprehensive appraisal of high-speed rail’s regional economic effect become more important and urgent . This study firstly analyzes Keynes’s investment promoting theory and the structure as well as basic modulus of input-output model. Secondly, this study studies direct promotion benefit on GDP brought by high-speed rail construction using investment promoting theory and input-output table. Finally, it analyzes direct promotion benefit on GDP brought by high-speed rail construction of the Hu-ning railway investment construction.