Introduction to contract account books: The salt industry contracts and business account books in the museum are also precious historical relics of the salt industry. The formation time of the salt industry contract in the museum ranges from the Qianlong period of the Qing Dynasty to the 37th year of the Republic of China. Over the past two hundred years, these contracts have reproduced several aspects of social and economic activities, reflecting the management of tribute salt industry and the tenancy relationship of wells and stoves since the Qing Dynasty. They are an important way to study the development and evolution of production relations, especially the capitalism of well salt industry. The sprouting precious historical materials have important collection and research value. The salt industry business account books systematically reflect the production and management of the well salt industry and are treasures among the salt history cultural relics.