The aim of this research was to study the relative effects of climate and local environmental factors on species diversity and test the applicability of the hypothesis of the evenness of two geographic patterns on a secondary shrub community in sub-humid environments. This research investigated 45 samples from secondary irrigation areas after forest damage in the eastern and southern areas of Jilin. Climate data and local environmental factors were used to study their effects on the species richness and evenness of the community, shrub layer, and herb layer. Different water ecotypes (xero-, mesoxero- and phreatophyte) were also analyzed separately to examine how the effects of climate and local environmental factors on the species richness and evenness differed among functional groups.The results showed that: 1) Community, herb layer species richness, and herb layer evenness, increased significantly with increasing latitude. 2) Community and herb species richness are mainly affected by local environmental factors rather than climate. The abnormal relationship between species richness and latitude is owing to increasing shrub layer cover with increasing precipitation, leading to decreased species richness. The correlation between shrub species richness and latitude and climate factors was not significant, because the response of different water ecological regimes to the climate gradient was inconsistent, which reflects the influence of functional groups on diversity patterns. 3) The evenness of the community and shrub layer was mainly affected by the climate factors. The evenness of the herb layer was mainly affected by the local environmental factors. The precipitation also indirectly affected herb evenness through the influence of the shrub layer. However, the results of the community, shrub, and herb layers all support the hypothesis that evenness increases with improving environmental conditions. The results of this study showed that the mechanism of species richness and evenness is very different, but both are strongly influenced by local environmental factors. Climate indirectly acted on the diversity of the pattern through local biological factors (such as coverage, lifestyle); therefore, the effect of the climate on diversity is important, but has not received due attention. Since local biological factors also change with climate, only studying the surface relationship of diversity and climate will not accurately predict the impact of climate change on diversity.