Belonging to the field of microbial environmental protection, the invention provides a microbial agent for treatment of sewage and sludge. The microbial agent mainly includes Rhodospirillum rubrum, rhodopseudomonas palustris, bacillus subtilis, Streptomyces microflavus, streptococcus thermophilus, candida utilis, Streptomyces viridis, pseudomonas aeruginosa, virgibacillus halodenitrificans, and Paracoccus denitrificans 10 bacteria. Each bacterium is subjected to conventional slant culture, shaking culture and seed tank cultivation respectively, the bacteria in the seed tank are mixed and then put into sewage directly, symbiosis of flora is utilized to reach the purpose of treating sewage and reducing sludge generation. The microbial agent provided by the invention can be applied to large-scale production and direct adding, is low in cost, and can adapt to changeful sewage components. And the flora has good impact resistance to sewage.