Abstract:According to the profile of modern vegetation and pollen analysis of surface samples, the character of sporo-pollen assemblages from the steppe of Huluengbar to forest of Daxinganling mountain being investigated, indicated that, there existed a sylvosteppe zone in between the steppe and forest zones, in which the percentage of A. P. is a little more than that of N. A. P. (about 30%～70%). At the same time a nonlinear correlation was found between the percentage of pollen and the abundance of maternal plant. There were three states in the of plant/pollen system: (1)inferior position with abundance of pollen or the maternal plant both less than 30% or 20% .(2) dominant position with both over 70% and (3) mixed pisition with both between 30%～70%. In the first state, there existed a value of Po (pollen from another place) or Vo (short of pollen, or if none at all) in the second state, the linear correlation of pollen and plant became nonlinear and only in the third state, did the correction factor (value of R) approach constant.