Abstract: The aim of this research was to study the influence of Momordica charantia polysaccharide（0, 0.1, 0.3,0.6 mg/mL） and sodium nitrate（0, 5 mmol/L） on rumen methanogens of diversity in goats. Terminal restriction fragment length polymorphism（T-RFLP） and quantitative real-time PCR（RT-qPCR） was used to analyse the 16 S rRNA gene diversity and quantities of methanogens on ruminal fermentation at both 6 h and 24 h of in vitro. The results showed Momordica charantia polysaccharide influenced quadraticly methanogenic diversity indexes at 6 h and had a significant effect on Methanobrevibacter ruminantium. However, no significant effects of polysaccharide（at 24 h）and sodium nitrate（at 6 h and 24 h） on methanogenic diversity indexes were observed, but sodium nitrate reduced significantly the relative abundance of T-RF100. In addition, supplementation of polysaccharide increased significantly the quantities of methanogen, and affected quadraticly the quantity of methanogen at 24 h. In conclusion,Momordica charantia polysaccharide and sodium nitrate influenced on the methanogen communities and diversity in vitro rumen fermentation, and had the interactive effects on the methanogen communities.