Abstract: AIM　To discuss the intraspecific relationship in Magnolia officinalis and the genuineness of Cortex Magnoliae officinalis, and to find some DNA characters of certified “Houpo”. METHODS　Thirty-three samples from eleven locations, which can represent most of the distribution of M.officinalis, were selected. The total DNA was extracted. Severty-four random primers were tried to get good amplification. RESULTS One hundred and sixteen bands amplified from seventeen primers, were clustered by NTSYS-pc software. Three branches were obtained. Some distinctive primers and bands, which represent certified species or fine breed, were obtained also. CONCLUSION　1) M.officinalis should be divided into three geographic clans instead of two subspecies or varieties, they are, a) typical officinalis, b) typical biloba and c) Middle type. This conclusion agrees with the leaf form and other characters. 2) The genetic difference between “Chuanpo” and “Wenpo” is evident and the difference is in correspondence with the quantities of their chemical constituents. So, the genetic difference is the main reason of the genuineness of Cortex Magnoliae officinalis. 3) These results may be used to establish DNA database for identification of Cortex Magnoliae officinalis.