中文摘要：

本文在新新贸易理论框架下，通过引入连续的内生企业技术升级，构建了一个同时包含企业异质性、出口强度和技术升级的理论模型，刻画了出口强度影响企业技术升级的作用机理。利用中国企业层面的微观数据，通过系统广义矩估计方法，本文还考察了出口强度对中国企业技术升级的影响。结果发现，出口强度对中国企业技术升级的影响呈“倒U型”，且其对不同地区、不同所有制类型企业技术升级的影响并不一样。本文研究表明企业的出口强度并不是越高越好，当企业的出口强度超过一定的临界值后，出口强度的进一步增加反而不利于企业的技术升级。

英文摘要：

Under the framework of New-New Trade Theory, this paper builds a theoretical model which contains firm heterogeneity, export intensity and technology upgrading through introducing the continuous endogenous enterprise technology upgrading, We also investigates the mechanism of how export intensity affects enterprise technology upgrading. Based on China＇s firm-level data and using the system GMM estimation method, the paper analyzes the effect of export intensity on enterprise technology upgrading, which is shown by empirical results to be not monotonic, but of an ＂inverted U-shape＂. Further analysis demonstrates heterogeneous effects of export intensity on enterprise technology upgrading among different ar- eas and different types of ownership. The paper realizes that export intensity does not simply follow the rule ＂the higher the better＂. In fact, when export intensity exceeds a certain critical value, further increase of export intensity is harmful to enterprise technology upgrading. Therefore, from the view of enterprise technology upgrading, this paper provides a new perspective for understanding export intensity.