本研究以香港為研究對象，結合多種時間序列研究方法，包括向量自我迴歸（VAR）、因果關係測試、衝擊反應函數分析及變異數分解等，來探討人民幣對港幣的替代性。研究期間從2004年2月至2013年6月。本研究結果顯示，人民幣貨幣數量與港幣貨幣數量之間，不存在單向的領先－落後關係。然而，衝擊反應分析的結果顯示，港幣貨幣數量受到人民幣的負向衝擊效果，且效果具持久性；再者，在解釋波動的變異數分解中，實證結果發現，人民幣貨幣數量在解釋港幣貨幣數量的變異上，則有不弱之解釋能力。

This research combined various research methods of time series, including VAR, Granger Causality Test, Analysis of Impulse Response Function and Variance Decomposition to explore the substitution of Renminbi Yuan to Hong Kong Dollar in Hong Kong. Sample period is from February 2004 to June 2013. Research result indicated that the causality didn't exist one-way lead-lag relation between Renminbi Yuan and Hong Kong Dollar. However, the response of Hong Kong Dollar to Renminbi Yuan presented negative response and lasted. Moreover, the empirical result indicated that in terms of the variance of Hong Kong Dollar, Renminbi Yuan had moderate explanatory power.