The invention provides a compound microorganism agent for treating a black and odorous water body. The compound microorganism agent comprises compound bacteria and a compound enzyme preparation, wherein the compound enzyme preparation comprises candida tropicalis, candida utilis, bacillus natto, bacillus subtilis, bacillus licheniformis, nitrobacter, achromobacter denitrificans, nitrosomonus, acinetobacter, lactobacillus, aspergillus niger, aspergillus oryzae and photosynthetic bacteria; the compound enzyme preparation comprises protease, amylase, lipase, sucrase, and cellulase.