Abstract:[Objective] In order to cultivate high concentration of bacteria to deal with algal blooms caused by water eutrophication of algal blooms quickly. [Methods] Firstly, three important factors: KNO3, MnSO4?H2O and K2HPO4 which played important roles in NP23 bacteria concentration were selected based on the Plackett-Burman (PB) design experiments. Then, the best value of the selected important factors was picked out using response surface methodology (RSM) to optimize the process conditions of NP23. At Last, biological safety of NP23 bacteria liquid was evaluated by the acute toxicity and mutagenicity test. [Results] The bacteria concentration got 1013 CFU/mL after optimization, which were four orders of magnitude more compared with bacteria concentration before optimization and which showed that NP23 had no poisoning effect and no mutagenic effect on fish even in large doses. [Con-clusion] The results provide reference to practical applications of NP23.