Abstract: To investigate the species and floral compositions, association types, as well as seasonal dynamics in the relationships between species diversity and invasibility of herbaceous communities in Luoma Lake wetland, plant surveys were perfomred in the summer (August) of 2022 and the spring (April) of 2023, using transect and quadrat methods. The results showed that (1) there were 232 wild vascular species from 158 genera and 54 families. (2) Within the native wild species pool, cosmopolitan was the most abundant floral type at the family level, while temperate became the most abundant type at the genus level. (3) Both spring and summer natural herbaceous communities can be classificed into 12 major association types, which though varied in species compositions between seasons. (4) Species diversity indices of communities were highest in grassland habitat, intermedium in marsh habitat, and lowest in lake habitat. (5) Although season had no significant effect on species diversity or invasibility index per se, it can influence their relationships: community invasibility index was nagetively affected by Partrick abundance index and Simpson diversity index, while positively affected by Shannon-Wienner diversity index of native species in the communities; and the strengths of these effects were stronger in summer than in spring.