The invention discloses a degradable type shield tail sealing grease of a shield excavation machine, belonging to the field of chemical grease. The degradable type shield tail sealing grease of the shield excavation machine is prepared by compounding the following raw materials in parts by weight: 16-20 parts of base oil, 10-16 parts of thickening agents, 68-76 parts of filling materials, 3-5 parts of lubricating agents, 0.5-2 parts of antioxidants, 0.3-1.7 parts of antirusting agents, 0.5-1.5 parts of antimildew agents, 5-7 parts of viscosity index modifying agents and 16-24 parts of plasticizing agents. The preparation method of the degradable type shield tail sealing grease comprises the following steps of: firstly adding the base oil, the thickening agents, the viscosity index modifying agents, the antirusting agents, the antimildew agents, lubricating agents and the antioxidants to an agitator according to weight ratio at normal temperature, and uniformly mixing and agitating; then adding the filling materials in batches, and uniformly mixing; finally adding fibers, and mixing and agitating for about 90 minutes. The degradable type shield tail sealing grease not only has property of the conventional shield tail sealing grease and the advantages of low cost, high adhesivity, good pumping effect and excellent sealing property, but also can be degraded by microbes contained in soil without polluting the soil and underground water, belongs to an environmental-friendly product.