The invention provides a plugging device for secondary underwater concrete pipe insertion. The technical scheme includes that a first guide pipe (1) is arranged on the upper portion of the plugging device, a plugging device shell (2) is arranged outside the plugging device, a lock (4) is arranged in the inner middle of the plugging device and connected with an unlocking pull wire (3), an ejection rod (5) is arranged below the lock (4), a limiting plate (6) is mounted below the ejection rod (5), and a pull wire (7) is connected with a pull wire connection ring (8). A discharging hopper (13) is connected with the first guide pipe (1) which is connected with a guide pipe (11), a reinforcement cage (9) is arranged below a pile casing (10) which is arranged below a limiting plate (12), and a pull wire support (14) is arranged on the right side of the limiting plate (12) and provided with a pull wire limiting point B (15) and a pull wire limiting point A (16). The plugging device is reasonable and practical in design, the problem of pile breakage is avoided, quality of finished underwater concrete piles is guaranteed effectively, and type-A pile proportion of the finished piles is increased.