The invention discloses a mixing agitator with a fixed stirring barrel body. The mixing agitator comprises a bottom plate. Two supporting connecting columns are fixed to the middle of the bottom plate. An adjusting base is fixed to the left side and the right side of the bottom plate. A driving motor is arranged on the adjusting base. Transmission shafts are hinged to the two supporting connecting columns. An output shaft of the driving motor is connected with the corresponding transmission shaft. The opposite ends of the two transmission shafts extend out of the supporting connecting columns to be hinged to a left end plate and a right end plate of the stirring barrel body. The opposite ends of the two transmission shafts extend into the stirring barrel body to be fixed to two end plates of a filter screen barrel. A central shaft is arranged in the filter screen barrel. The two ends of the central shaft are fixed to the ends of the two transmission shafts. The filter screen barrel is located in the stirring barrel body. A plurality of grinding balls are put in the filter screen barrel. By fixing the stirring barrel body, the filter screen barrel rotates to achieve stirring, and stirring is uniform; when the stirring barrel body does not run, the driving motor can be separated from the stirring barrel body, and therefore misoperation is avoided, and safety is improved.