Abstract: As a topic focus in ecology, the relationship between biodiversity and productivity has drawn much attention from ecologists. We established experiment plots in a sub-alpine meadow of Southern Gansu province, China where there were 5, 9, 14, 19, 30-year abandoned lands and climax plant communities. Based on the succession gradient, we surveyed plant abundance and aboveground biomass to analyse a change model of biodiversity and productivity, and to explore the relationships between them. The biodiversity showed a unimodal curve, indicating the number of species increased first but decreased later along the succession gradient. At the early stage of succession, the productivity enhanced rapidly and reached a peak of 183.77 g/m² in the 19-year plots, after which, it remained stable. In the process of succession, the biodiversity was positively related to the productivity, though this relationship disappeared in the climax community. As the succession proceeded, the community pattern gradually changed into a species log-normal distribution from the early niche-preemption.