Abstract: The spatial pattern and association of plant population are the external manifestation of its position and survival ability in the community, which reflects ecological regulation ability and environmental plasticity mechanism of the population. In the Sugan Lake wetlands, three plots were selected with different soil salinity, including light salt zone, moderate salt zone, and heavy salt zone. The point pattern analysis method was used to study the distribution pattern and spatial association of Salicornia europaea and Triglochin  maritima populations at small scale. The results showed that, with increasing soil salinity, the spatial pattern of S. europaea population exhibited a transformation of “random distributionaggregation, uniform distributionaggregation distribution”, while T.  maritima population changed from aggregation distribution to random distribution. The spatial association between those two populations was mainly negatively correlated or non-correlated. Moreover, the interspecific relationship changed from competition to no definite relationship. The spatial distribution of soil salinity in Sugan Lake wetland significantly affected the spatial distribution pattern and interspecific association of plant populations. The replacement of dominant species in wetland community was influenced by plant population characteristics, interspecific relationships, and environmental conditions.

Key words: point pattern analysis, interspecific association, inland salt marsh, Triglochin , maritima, Salicornia europaea, small scale.