This paper mainly discusses the comparison and analysis of the chromosomal karyotype, esterase isozymes and geographical distribution of the two species in Ammopiptanthus genus (A. mongolicus and A. nanus). At the sametime, the chromosomal karyotype, esterase isozymes of the kindred genus-the representative species in Qinghai-Xizang Plateau (Piptanthus nepalensis, Thermopsis barbata) were studied in order to further approach the evolutional trend, geographical distribution and the relations between the envi...