Abstract: Artemisia arenaria is an important plant species of fixing sand in the Shiyang River Basin, Gansu Province. In this study, some sample plots with different distance away from the river course of the Shiyang River were delimited to analyze the spatial distribution pattern of Artemisia arenaria population. In the plots, the height, crown breadth and spatial relevancy of all the differentaged Artemisia arenariaplants were recorded. The point pattern analysis was used to analyze the spatial distribution pattern and relevancy of the plants in different plots. The results were as follows:(1) Artemisia arenaria population was in a decrease trend with the increase of distance away from the river course; (2)Artemisia arenaria population was in a significant aggregation distribution pattern at relatively small scale, the aggregation distribution pattern decreased gradually with the enlargement of scale, a random distribution occurred, and the aggregation degree near the river course was higher than that far away from the river course. At different distance, young plants grew in an aggregation pattern, but the adult ones in random pattern; (3) There was a positive spatial relevancy among the high plants near the river course, but a negative one among the short plants far away from the river course.

Key words: river course, Artemisia arenaria, population, spatial distribution pattern, relevancy, Shiyang River