By means of the PCR-RFLP technique the polymorphism of a 465 fragment of mtDNA D loop was analyzed in 36 individuals of the Northeast Han, 30 individuals of the Daur, 32 individuals of the Oroqen and 30 individuals of the Ewenki. All these individuals were randomly selected and are healthy. 27 restriction patterns were obtained by assaying the RFLP fragments of the mtDNA D loop. The mean nucleid acid substitute frequencies at each site are the following: Northeast Han = 0.0291, Oroqen = 0.0477, Ewenki = 0.0563, Daur = 0.0541. The genetic relationship between these four populations was analyzed by the UPG cluster analysis.