The authors collected 34 paddy soil samples along the latitude from eastern China. Enrichment experiment was conducted under anaerobic conditions with sodium butyrate as the sole substrate. The authors investigated the microbial community characteristics and the functional activity of syntrophic butyrate degradation and the biogeographic patterns of relative abundance of Syntrophomonas in these soils by Illumina sequencing of 16S rRNA genes. The lag phase of CH₄ production (3–14 days) increased towards higher latitudes, whereas the maximum rate of CH₄ production did not. The correlation analysis on influencing factors revealed that Syntrophomonas was the key syntrophic bacterial taxon associated with butyrate degradation and its relative abundance was significantly influenced by mean annual temperature (MAT). The sampling sites with a relatively high abundance of Syntrophomonas had a shorter time for the complete degradation of butyrate. Distance-decay patterns characterized by a steeper slope were found in microbial communities associated with syntrophic butyrate degradation (p<0.05), indicating that the construction of microbial communities was driven by both spatial distance and environmental factors.