Abstract: Based on the datasets from sampling plots, the interspecific relationships among dominant weeds species of tobacco field in Guizhou province were studied by using the methods of variance analysis, Pearson’s correlation and X²-test. The results indicated that: ①The total associations among all the dominant weeds species of tobacco field in Guizhou are remarkably positively significant in stable state; ②There were positive associations for 21 pair-species, negative associations for 23 pair-species and no association between Stellaria media (L.) Cyr. and Polygonum nepalense Meisn. by Pearson point correlation coefficient; ③The remarkably significantly positive interspecific associations were found between Galinsoga parviflora Cav. and Digitaria sanguinalis(L.) Scop., G.parviflora and P.nepalense, the remarkably positive interspecific associations were found between G.parviflora and Commelina communis L., D.sanguinalis and P.nepalense and the others were unremarkable. The study arms to realize and master the distribution of tobacco field weeds in community and change the trend of tobacco field weeds, and supply the basic data for tobacco field weeds control.

Key words: tobacco field, dominant weeds species, interspecific relationships, variance analysis, Pearson&rsquo, s correlation, X²-test