The invention provides a microbial 
sewage treating agent for deep synergistic purification of 
sewage and a preparation method. Anaerobic digestive 
bacteria-
silicone colloidal particles are formed by anaerobic digestive 
bacteria, seaweed nutrients, 
silicone and a dispersing agent through mixing and 
granulation, meanwhile, high molecular weight 
polyethylene and porous 
ceramic powder are mixed and ground, then, 
denitrifying bacteria are added, a denitrifying bacterium premix is obtained, an inorganic 
adhesive is sprayed to the surfaces of anaerobic digestive 
bacteria-
silicone colloidal particles,the anaerobic digestive bacteria-silicone colloidal particles covered with the inorganic 
adhesive and the denitrifying bacterium premix are rolled and mixed, 
granulation and 
pelletizing are performed, and the microbial 
sewage treating agent for deep synergistic purification of sewage is obtained. According to the method, the anaerobic digestive bacteria are immobilized through silicone and covered with a denitrifying bacterium premix film, the defect that 
denitrifying bacteria and anaerobic digestive bacteria have difficulty in playing a role in sewage is overcome, the removal process is simple, the removal efficiency is high, the preparation and use cost is low, and large-scale popularization and application can be realized.