在进口关税配额、国营贸易垄断和产业政策变动的前提下，应用引力模型，以向我国有玉米（替代物）出口的国家2001～2019年相关影响因素数据进行实证分析，结果表明，管控状态下，传统双边贸易因素中的产量在玉米进口中依然符合理论预期，贸易国之间距离的作用并不符合理论预期。产业支持政策（玉米生产者补贴+市场化收购价格制度）、自贸协定等因素在我国玉米（替代物）进口中具有显著性影响，但产量和距离因素在所有替代物进口中影响并没有得到一致估计。同时，根据构造的玉米进口贸易替代指数的测算结果，2001～2009年间，小麦与大麦在玉米进口替代上呈现出明显的竞争关系。2009～2014年间玉米进口与替代物进口具有明显的替代关系；2017～2019年，呈现出明显的替代关系。政策管控只是改变了我国玉米进口来源国的构成，并没有扭曲我国玉米进口。在中美贸易摩擦的大背景下，实施积极有效的战略性贸易政策和国内产业政策十分必要。

Based on tariff quota, the state-run trade monopoly and industrial policy changes, we used the improved gravity model with the China corn(substitute) panel data related to trade import countries 2001-2019 years of corn(substitute) imported to estimate the impacts of the factors, The results showed that under the control state, the yield of the traditional bilateral trade factors estimation is consistent with theoretical expectations in corn imports, corn production of China's import source country is positively correlated with China's total corn imports in international trade; but the distance between trading countries does not meet theoretical expectations, because of sample size constraints, short-term politics and geopolitics, the distance between trading country are significant but positively related. Industry support policy(‘Corn producer subsidies + market price’ policy) and control(corn trade quotas) in China corn(substitute) have a significant effect in the import, but yield and distance factors in the model for corn substitutes have not been consistent estimates. At the same time, according to the survey results, we construct the corn import substitution index of 2001-2009 between wheat and barley in corn import substitution showed a clear relationship between competition; Corn imports and import substitution has been obvious alternative in 2009-2014 and 2017-2019, However, whether wheat, barley, etc. can be used as corn import substitutes for a long time still needs further research. Based on the above research results, it can be seen that policy control has only changed the composition of my country's import source country, and has not distorted my country’s corn imports. In the context of China US trade tensions, implementing active and effective strategic trade policies and domestic industrial policies is very necessary.

黑龙江省社科基金项目（17JYD240）