Site of Iron-door Barrier is in Qianguan village, Lijin County, with the meridional and transmeridional width are 42 and 30 meter respecctively and the area is 1260 sq.m.. It is a historical important gateway in Shandong province and is famous inside and outside province in its flourishing times. 《Thesaurus of Chinese Placengames》 notes that the Iron-door Barrier is situated to the north of Lijin town, Shandong province. It was first founded in Jin Dynasty, for at that time it is close to Bo Sea and is the seaport where Daqing River gathered to sea. In order to control the seashore, governors of Jin built a solid rampart and installed an iron door, and also quartered armies. Annals of Lijin Town recorded: In the past, Ji Water flew into sea, with a section going through Lijin town named Daqing River where traders formed a continuous stream. Some came from Zhejiang, Fujian, Guangdong provinces and so on, the others came from Japan, Korea and some European countries. The cargo they carried including cloth, silk and damask, grocery, tea and sheet etc. are called Foreign Goods for most of them were fetched from overseas or around Guangdong. Yongbu and Fenggguo were two well-known salt fields in Shandong province and the salt produced there was shipped out through