The invention discloses an immersed tunnel final joint and a shoreside dry-work construction method thereof. The method includes immersing the last section of an immersed tunnel in place, mounting temporary steel cofferdams after processing of a slurry stopping belt and a rubber waterstop is completed, pouring underwater concrete at a junction of the last section of an immersed tube section and a retaining structure of underground continuous walls and quay walls on two sides, pouring waterproof concrete between each two adjacent temporary steel cofferdams, and grouting for sealing; after the underwater concrete on two sides of the temporary steel cofferdams reach strength, pumping away stagnant water between the temporary steel cofferdams and the quay walls, and mounting temporary inclined struts according to descending height of water level; welding the temporary inclined struts on the temporary steel cofferdams, erecting top plate and bottom plate steel supports, dry-working a final joint in a gap connecting the last section of the immersed tube section with a shoreside hidden-buried section, pouring concrete, and connecting the last section of the immersed tube section and the shoreside hidden-buried section into a whole. Structural integrity and construction quality of the final joint at a deep-water area are guaranteed, and construction risk is effectively lowered.