Abstract: In this study,a survey on seed plants along the Great Wall built in the Warring States Period and the Qin Dynasty in the Dingxi area of Gansu Province was carried out.In the survey 444 plant species in 242 genera and 58 families were found,in which 3 species in 3 genera and 2 families belonged to Gymnosperm,and 441 species in 239 genera and 56 families belonged to Angiosperm.Among the 58 families,there were 15 monotypic genus families and 5 families with more than 10 genera at least,and they accounted for 45.5% and 52.4% of the total surveyed genera and total species respectively.Compositae with 82 species and 38 genera was the richest family.There were 4 areal types and 4 subtypes at family level,and 13 areal types and 11 subtypes at genus level,in which 2 genera belonging to Compositae and Umbelliferae were endemic in China.There were the rich plant species and complex geographical elements in the study area,the flora were dominated by the Old World Temperate and the North Temperate types.Two rare and endangered species with low protection level were found.These conclusions could contribute to the theoretical and practical proofs for protecting the Great Wall with plants.

Key words: seed plant, flora, areal type, Great Wall protection, central Gansu Province, Loess Plateau