To explore the optimal removal efficiency of turbidity, CODMn and UV254 in low temperature and turbidity water by micro-vortex flocculation, computational fluid dynamics (CFD) numerical simulation was used to explore the flow state of flocculation area under different flow rates (flocculation time), and the optimal flocculation time was determined. The effects of flow rate, the dosage ratio of coagulant to vortex reactor and their interaction on the removal of turbidity, CODMn and UV254 by micro-vortex coagulation process were studied using Box-Behnken central composite design method in response surface. The research show that the average turbulent kinetic energy, effective energy consumption and their change rates increase with the decrease of the flocculation time, whereas the vortex scale and its change rate decrease with the the flocculation time in the flocculation area. The optimal flocculation time is 18.5～13.6 min. It is found that the dosage ratio is a extremely significant factor affecting the micro-vortex flocculation process, and has a synergistic effect with the dosage and flow rate. The optimum parameters of micro-vortex flocculation for low temperature and turbidity water are as follows: flow rate is 6.4 m3/h, coagulant dosage is 26.8 mg/L, and dosage ratio is 2 (2/5 HJTM-1 vortex reactor+3/5 HJTM-2 vortex reactor). Under this condition, the removal rates of turbidity, CODMn, and UV254 are 85.48%, 63.84%, and 55.37%, respectively.