The invention belongs to the technical field of environmental management, and particularly relates to a diversified microbial system for improving eutrophic water and an application thereof. Accordingto the diversified microbial system provided by the invention, the adaptability of microbial products in different environments can be enhanced, so that the degradation stability of eutrophic water is improved. The problem that the existing microbial water purification technology is poor in adaptability and unstable in effect in different water qualities are solved. The microbial system providedby the invention comprises diversified microbial agents and an additive. The diversified microbial agents comprise bacillus subtilis bacterial liquid, bacillus megaterium bacterial liquid, brevibacillus laterosporus bacterial liquid, lactic acid bacteria liquid, nitration monad bacterial liquid, bacillus licheniformis bacterial liquid, trichoderma viride bacterial liquid, saccharomyces cerevisiaebacterial liquid, pseudomonas fluorescens bacterial liquid, rhodospirillum rubrum bacterial liquid, rhodopseudomonas palustris bacterial liquid, spherical rhodobacter sphaeroides bacterial liquid, andpseudomonas putida bacterial liquid. The additive comprises starch, diatomite, calcium carbonate and compound amino acid.