This study compared formats and contents of legal documents of contracts used in Kinmen, Fujian and Caotun, Taiwan to explore their similarities and differences Based on the comparisons between the legal documents of contracts of land sale in the two explored places in the Qianlong period, and contracts of land mortgage in Xianfeng period, this study found that among these documents 61% were the same, 30% were different, and 9% were roughly the same with only minor differences. The most obvious differences were the different ways the areas of the land were documented in the contracts and the currencies used for trade. In Caotun, Taiwan, silver dollars were used as the trading currency for all transactions. On the contrary, they only accounted for 14% of transactions in Kinmen, while the other 86% of the transactions used copper coins as trading currency. The less use of silver dollars in Kinmen may be due to the fact that Kinmen, a small island with poor soil, did not yield much to be exported for foreign currencies to flow in. On the other hand, deerskin, sugar, rice, camphor, and tea produced in Taiwan were all preferred merchandise by foreign merchants, and consequently the foreign silver dollars kept flowing in and were used as trading currency in Taiwan.