The invention relates to a continuous wall I-steel joint with water-swellable water-stopping strips, and relates to the technical field of underground continuous wall engineering in a foundation pit support structure. An I-steel comprises web plates and a wing plate located on the two sides of the web plates; the I-steel is arranged at the two ends or one end of a first-stage underground continuous wall section, a horizontal steel bar of the first-stage underground continuous wall section is welded with the wing plate of the I-steel; the middle of the two sides of the web plates or the middle of one sides of the web plates are vertically provided with water-swellable water-stopping strips, flat steels are arranged on the two sides of the water-swellable water-stopping strips, and the flat steels and the web plates of the I-steel are welded and fixed; cover plates are arranged on the outer sides of the water-swellable water-stopping strips in a sleeved mode, the bottom parts of the cover plates are connected with thin ropes, and the other ends of the thin ropes extend to the top part of the I-steel; and a blocking plate is arranged in a groove close to the I-steel at one side of the second-stage underground continuous wall, and the groove of the blocking plate faces the web plates of the I-steel. The continuous wall I-steel joint has the advantages that water stopping effect is good, water bursting and sand boiling are not prone to occur, safety and reliability are achieved, and practicability is stronger.