In this article, we compare market efficiency of Chinese and EU hog markets - the world’s two largest pork producers and consumers - which serves as a large sample to study and compare spatial market integration mechanism. China and the EU face similar logistical challenges, but have different institutional set-ups. One is a national market composed of 30 provinces; the other a single market in which 27 sovereign countries apply common market regulations. There are also important differences in market structures and restrictions such as animal welfare. We study whether there are systematic differences in hog market efficiency between the EU and China. We compare market efficiency of Chinese and the EU hog markets using an original price series covering 53 markets and 688 market pairs over 13.5 years. We explore several prominent mechanisms that potentially explain technology difference of market efficiency and find the most support for trade costs and pig farm structure.