The method of11 standard trees and 5 dominanntt treeswas generally applied in selection of the elite trees from timber stands.However,there existed the subjectivity in the selection criterion of the elite individuals and the elite genetic characters needed to be selected again and again after the elite individuals were selected,and therefore a large amount of time would be spent.In this paper,Eucalyptus dunnii dominant trees with cold-resistant and rapid-growth genotypes were primarily selected in different stands in introducing areas from 1 to 4 years by large samples method.The primarily selected dominant trees were regarded as investigation center in different stands and the selection criterion of elite trees was determined by applyingtdetermination principle according to the normal distribution rule of growth characters of forest individuals in stands and E.dunnii elite trees with cold-resistant and rapid-growth were selected with the selection criterion having been determined bytdetermination principle.6,5,2 and 2 elite trees were selected from 1 to 4 years stands,respectively.The growth characters of those selected elite trees were better than the average of all the stands,height of the selected elite trees increased by over 90.5%,39.0%,45.2%,61.5%from 1 to 4 years stands,their breast diameter increased by over 37.9%,81.2%, 73.3%and their volume of timber increased by over 134%,378%,339%from 2 to 4 years stands,respectively.The method was reformed by mutative theory of gene recombination of plant andt determined ruleof normal distribution of mathematics statistics,which could make the mutative elite genetic characters be determined once.This method overcame the subjectivity of the above two selection methods and greatly shortened the selection time.This paper first proposed and named the method oftdetermination principle,which is a useful tool for selection of elite trees from timber stands.Tab 4,Ref 14