Under the structure of heterogeneous firms, we extend Arkolakis et al. (2010) to an endogenous growth model to reconsider the short-run and long-run impact of trade liberalization. Because of endogenous elasticity, the engine of growth can only be generated by the knowledge spillover originated from industrial productivity growth. Therefore, different from previous literature, there is no trade-off between short-run productivity increase and long-run growth. Depending on the parameters of the model, after subsidizing or taxing entry of producers, there is also no trade-off in terms of welfare.