A large number of complex microbial communities are colonizing in many parts of the human body, the whole microbial genes of which are defined as human microbiome. The symbiosis has formed in the co-evolution between human microflora and the host, in which microflora plays an important role in regulating digestion, absorption, immune response and metabolism of the host. Human microecology is closely related to many human diseases such as infections, obesity, diabetes, liver diseases, coronary heart diseases...