The invention discloses shield tail sealing grease and a preparation method thereof. The shield tail sealing grease for tunnel construction tunneling equipment namely a shield tunneling machine consists of the following components: 15-30% of base oil, 10-20% of lubricating grease, 2-8% of a tackifier, 1-5% of an adhesion promoter, 5-10% of fibers, and 30-50% of a flour filler. The shield tail sealing grease is mainly formed by the combination of the base oil, the lubricating grease, the fibers and the filler, particularly the adhesion promoter is added, and the adhesion and the stability of a product are enhanced by the interaction force between the adhesion promoter and the surface of a base material; the product is stable in performance, avoids phenomena of segregation and sun crack when exposed in the air for a long time, does not generate sag and flow when encountering heat, and can still keep a relatively good pumping performance at a low temperature; and the shield tail sealing grease has relatively high impermeability, is convenient to operate and easy to pump, has excellent adhesion and certain corrosion resistance to metals, has outstanding water-stop and lubricating effects, and is easily biodegradable, environment-friendly and nontoxic.