中文摘要：

在内地人民币理财产品收益率高于香港市场人民币贷款利率的情况下，内地进出口企业大量运用“内保外贷”获取利息收益，因此基于交易需求的货币替代理论（边际效用理论）并不能完全解释人民币在内地进出口贸易结算中替代美元程度不断提高的现象。文章将利率差引入企业货币选择的理论模型并通过实证检验发现：2012年以来．利率差引发的贸易投机是内地贸易结算中人民币替代美元的主要动因，而汇率水平和汇率波动对贸易结算中人民币替代美元的影响并不显著。

英文摘要：

China＇s trade enterprises use ＂overseas loans under domestic guarantee＂ to obtain profits, since the yield rate of financial products in the mainland is higher than the lending rate of RMB in Hong Kong market. Therefore, the currency substitution theory based on demand （marginal utility theory） cannot fully explain the increasing substitution rate of RMB against Dollar in China＇s trade settlement. This paper introduces interest-rate to the model of currency choices and makes an empirical test. It finds that the trade speculation triggered by interest rate differentials has been the main reason for the inverse currency substitution since 2012, and the effect of exchange rate and exchange rate volatility on inverse currency substitution is not significant.