The approximately spherical intermediate cobalt carbonate was first synthesized by the hydrothermal method, and Co3O4 with the same shape was obtained by calcining the cobalt carbonate. Afterward, the influencing factors and the reaction mechanism of the degradation of TC by Co3O4 under MI and were systematically discussed, and the optimal conditions for the degradation reaction were found. The new MI catalyst synthesized in this research has good morphology and microwave absorption performance, which can effectively achieve the goal of using microwaves to degrade TC, making the degradation of pollutants simpler, faster, and more thorough. This study provides a green and environmentally friendly effective way for antibiotic treatment, which has a good reference value.