The utility model discloses a water stopping structure of a steel wire brush of a shield tunnel portal. The water stopping structure is characterized in that a water stopping steel wire brush is welded on a steel ring of the portal, so that the water stopping steel wire brush is arranged between the portal and a shield machine to form a water stopping structure. The water stopping structure disclosed by the utility model has the advantages that the structural form is similar to a sealing steel wire brush structure at the tail of the shielding machine, and can play an effective role in water stoppage; and the water stopping structure disclosed by the utility model is especially suitable for special sections, including stratums such as the silt stratum and the confined water with more underground water; and the water stopping effect is good and the safety coefficient is high.