In this paper, genetic diversity of three natural populations of Pinus koraiensis and four natural populations of Quercus mongolica in China was studied with the method of random amplified poly-morphic DNA (RAPD). Combining with the results of morphology and allozyme research, life history and evolution history, we discussed ecological adaptation and development potential of population of Pinus koraiensis and Quercus mongolica. 1. Young needles of 60 trees of Pinus koraiensis were collected randomly from three typical areas. Genomic DNA of total individuals were extracted using developed CTAB method. RAPD analysis of these trees was conducted with 38 selected random primers. In these amplfications, 241 repeatable loci were obtained. Percentage of polymorphic loci was 57.68%. According to the measurement of Shannon index and Nei's index, genetic diversity of Pinus koraiensis mainly distributed within population. In the studied populations of Pinus koraiensis, the level of genetic diversity in PLS was the highest, that of PHL and PHH were nearly same. The average genetic similarity within populations was 0.927, that among populations was 0.845. The average genetic distance within populations was 0.073, that among populations was 0.155. A special RAPD band of PHL was found in amplified products. 2. According to the research of genetic diversity on morphology, allozyme and DNA, genetic diversity of Pinus koraiensis was on middle level among the woody plants. This situation was largely connected with the serious attack suffered by Pinus koraiensis during glacier of the Quaternary period and the characteristic of its life history. 3. Combining with the level of genetic diversity, the characteristic of life history and biology, we primarily concluded that pinus koraiensis was a species whose genetic diversity was in a slow process of recovery. In suitable environment, Pinus koraiensis had the potential to enlarge its populations. But the accumulation of genetic diversity of Pinus koraiensis needed a long period because of its long life cycle. the most important factor affecting the existence and development of Pinus koraiensis in a long period was the environment condition provided by human being. 4. Young leaves or buds of 80 individuals of Quercus mongolica were collected randomly from four typical sites in its distribution area. AFter the extraction of genomic DNA, all of these individuals were analysed with RAPD using 48 random primers. In the 344 clear and repeatable loci, polymorphic percentage was 71.22%. Using Shannon index and Nei's index to calculate genetic diversity, we found that genetic diversity of Quercus mongolica mainly occurred within populations. In the four studied populations of Quercus mongolica, the level of genetic diversity of OLJ was the highest, that of OHH was the lowest, and that of OSZ and OHL were the middle. the average genetic similarity within populations was 0.904, that among populations was 0.870. The average genetic distance within populations was 0.096, that among populations was 0.129. In the total bands, three of them were found to be special bands of OHL or OHH. 5. Analysing with genetic diversity on morphology, allozyme and DNA, we concluded that the level of genetic diversity of Quercus mongolica was on upper middle among perennial, cross-pollinated woody plants. This was benefit to the existence of the populations of Quercus mongolica. 6. Combining with genetic diversity, life history and evolution history of Quercus mongolica, we thought that Quercus mongolica was a steady species. Its abundant genetic diversity and strong adaptation ability to environment assured the steady existence and development of populations. This study deeply discussed ecological adaptation and developing potential of population of Pinus koraiensis and Quercus mongolica, accumulating genetic material for the study on adaptation mechanism of plant. Meanwhile, it also provided scientific basis for protection and exploitation of natural resources.