Abstract: Abstract：This paper discussed the effect of urban construction land scale on economic growth based on the nonlinear Smooth Transition Regression Model and data of China from 1982 to 2016. The results showed that: (1) There is an obvious nonlinear feature between China’s urban construction land scale and economic growth. It is most appropriate to establish a non-monotonic transfer function model by using two-order economic growth as a transition variable. (2) When the transition variable is between the critical value of 30 542.404 billion yuan and 375 595.954 billion yuan, the transfer function is 0 and the model is completely linear. When the transition variable is equal to the critical value, the transfer function is 0.5 and the relationship between the scale of urban construction land and economic growth is converted from a linear mechanism to a nonlinear mechanism. (3) When the transition variable is less than 30 542.404 billion yuan or more than 37 595.594 26 billion yuan, the value of transition function is rapidly converted to 1, and the nonlinear impact of urban construction land scale on economic growth will appear. At this time, the scale of urban construction land changes by 1%, which will cause current economic growth of 1.829 03%.