Abstract: Based on the duality perspective of the innovation value chain theory, this paper divided the process of industry-university knowledge flow into knowledge innovation stage and knowledge transformation stage, and 137 "Double First-Class" construction universities were used as research subjects. And the super-efficiency DEA model was used to measure the innovation efficiency and the transformation efficiency, and the panel Tobit model was used to study the influence mechanism of government support on dual efficiency of industry-university knowledge flow. The results show that:(1)there is an imbalance in the dual efficiency of industry-university knowledge flow, and the average value of knowledge innovation efficiency is higher than that of knowledge transformation;(2)government support has a significant inverted U-shape effect on the innovation efficiency of industry-university knowledge flow, but it has no significant effect on the efficiency of the transformation of industry-university knowledge flow;(3)under the moderating role of the type of university, government support has strengthened the inverted U-shaped influence on the innovation efficiency of industry-university knowledge flow, and has a significant promotion effect on the efficiency of industry-university knowledge transformation;(4)the influence of government support on the dual efficiency of knowledge flow in industry-university is heterogeneous in terms of the degree of innovation concentration and geographical distribution.