Abstract: Ceratoides ewersmanniana and Haloxylon ammodendron were the edificators and dominant species in the Gurbantunggut Desert,playing an important role in wind breaking and sand fixing.Box-counting dimension method of the fractal theory was used in comparative analysis of spatial distribution of the populations of the two shrub plants in two sample plots(200 m×200 m),different in type of habitat.Results of the analysis indicate that the box-counting dimension of spatial distribution of the population of C.ewersmanniana was 1.709 and 1.527 0 in plot A and B,respectively,and of H.ammodendron,1.406 3 and 1.568 6,respectively.All in all,the former was comparatively higher than the latter in capability of occupying and exploiting space.The box-counting dimension of interspecies spatial distribution of the two shrub plants varied slightly between Plot A and Plot B,being 1.780 5 and 1.735 7,respectively,both higher than the box-counting dimension of spatial distribution of the population of a single species,which suggests that when deemed as a whole,C.ewersmanniana and H.ammodendron populations were much higher in capability of occupying and exploiting space,and their ecological functions was similar in either Plot A or B.

Key words: Ceratoides ewersmanniana, Haloxylon ammodendron, spatial distribution pattern, box-counting dimension