Based on field investigation and references,the floristic characteristics of seed plant in Huoditang were analyzed,and the relationship between the folra of Huoditang and 7 floras was also discussed.The results showed that:(1)there are 1 283 species belonging to 136 families and 547 genera in Huoditang.In those plants,the big families and big genera play important roles;(2)The geographical elements of the flora are comparatively complex,and the genera of temperate are the dominant areal types (335 genera，account for 61.2%);(3)The flora of Huoditang is very closed to Qingmuchuan,Tianhuoshan,Niubieliang and Laoxiancheng Nature Reserve,less close to Funiushan.It is far from Xiaolongshan and Ziwuling.The floristic variations with longitude in Qinling Mountains are that:the compositions of north temperate and temperate zone distribution increase with dropping of longitude,the compositions of tropics and subtropics zone distribution increase with rising of longitude.