关键词: 外部综合价格指数, 地理距离阈值, 一价定律, 格点搜索法

Abstract: We built a composite price index reflecting the external supply shocks and geographic distance influence, and distinguished local from aggregate sources of price variation. With panel data of eight provinces in the south of China and another ten northern provinces from 1995 to 2009, the article estimates the degree of grain market integration in China. The conclusion is that the degree of Chinese grain market integration was quite high controlling the local impact factors such as weather conditions and harvest qualities, the external composite price index increased 10%, the average price of southern rice and northern wheat increased by 10.31% and 9.85% respectively. Using the method of grid search, we got the threshold values of geographical distance of local rice and wheat market, which were 1011 km and 2200km,then empirical analysis of the degree of influence of Geographic distance on food’s market integration. 76% and 85% change of local market price of rice and wheat resulted from composite price changes in relatively close provinces, and the shorter distance provinces had, the higher degree of market integration was.

Key words: Outside Composite Price Index, Threshold values of Geographical Distance, The Law of One Price, The Method of Grid Search