Abstract: Eight types of forest communities in the north Fujian were studied with 8 species diversity indices and 4 species-abundance relationship models, which are log normal, Weibull distribution, log series, niche preemption models, were used to analyze species-abundance relationship, and the regressions between diversity indices and the parameters about log normal, Weibull distribution and niche preemption models were also studied in order to analyze the probability of describing the species diversity by the parameters of abundance models. The results showed that most of the diversity indices reflected the community’s characteristics, and that eight communities could be fitted well with log normal, Weibull distribution and niche preemption models. The strong or very strong linear correlations exited between the parameters about some of the models and the diversity indices. The results also showed that the bio-diversity could be quantified by the measurement of the species diversity of 8 forest communities in the north Fujian and that modified simplex was a simple and effective method and could be popularized to apply.