The invention provides a phenol-degradation microbial agent, immobilized globules and a preparation method. Microorganisms in the phenol-degradation microbial agent are separated and extracted from surface filter materials of a biological manganese sand filter pool of a waterworks, and after the microorganisms are cultured and screened in a manganese-contained MSVP liquid medium and a manganese-contained MSVP solid medium and are activated in a TBS medium, the phenol-degradation microbial agent is prepared. The invention further provides the preparation method for preparing the phenol-degradation microbial agent into the immobilized globules. According to the preparation method, the gel globules are prepared by using cross-linking polymerization products of silicon dioxide or manganese dioxide and sodium alginate as carriers and embedding the phenol-degradation microbial agent. The phenol-degradation microbial agent can be applied to rapidly degrading phenol at low-temperature oxygen-free and neutral conditions of underground water. The phenol-degradation microbial agent immobilized globules can provide stable degradation environment, are more suitable for toxic environment, and are used for treating phenol pollution of the underground water with higher concentration.