Abstract: Based on the phylogeny and modern distribution of Thermopsideae (Papilionaceae) , and available fossil records of the tribe,a preliminary phytogeographic study has bean carried out through the theory and method of morphology-geography. The study shows that (1) The tribe very probably had a Tertiary Tethyan origin, its birthplace was near the southern Laurasia and had a mid-latitude source;(2)It probably rised before the Paleogene but after the late Cretaceous when there was a so-called boreotropical flora occuring in the N. Hemisphere; (3)The tribe is basically a natural one; (4)Its woody taxa were primitive groups which probably originated from woody Sophora-like ancestors while the herbaceous were the advanced derived from it later; (5)Both Asia and N. America are probably the modern refugia rather than the original regions of Thermopsis which has an Asia-N. America disjunction pattern. The interchange between N. America and Asia in the genus probably occurred along the ancestral path of the Tethys. This disjunction pattern may not be simple, it may involv multiple historical events in different geographical times; (6)With the uplift of Himalayas and Qinghai-Xizang plateau caused by the late Tertiary orogeny in Asia and the uplift of Rocky Mts. in western N. America, the humidity and temperature conditions among these regions changed profoundly, and they became the principal impetus of specialization process,especially. in Piptanthus and Thermopsis.

Key words: Thermopsideae