This study mainly focused on the cloning and expression of a β-galactosidase gene isolated from the hot springs metagenome and its primary application in animal nutrition. β-galactosidase gene was amplified by using metagenomic DNA isolated from a hot spring with a temperature of 65 ℃ in Eryuan in Dali as a template. Sequence analysis result showed that the sequence potentially encoded a β-galactosidase,since the encoded amino aicd shared 71%sequence homology with that of Thermotoga lettingae TMO glycoside hydrolase. After heterologous expression in E. coli Rosetta and affinity purification,the purified product was further subjected to analysis of enzymatic characteristics.The results showed that the optimum acting temperature and pH value of the expressed β-galactosidase were 55℃ and7. 5,respectively. The crude lysate kept about 65% of its enzyme activity after treated at 58 ℃ for 30 min. The β-galactosidase could hydrolyze lactose in soybean into galactose and glucose,indicating a good application prospect in feed production.