The invention discloses a box culvert jacking post-cast strip waterproof structure system and a construction method, and relates to the technical field of road construction. The system is characterized in that outward-protruding longitudinal steel bars are reserved at the longitudinal end face of a rectangular box culvert; a U-shaped groove is formed in the exterior of the end face of the rectangular box culvert, and an interval is reserved between the U-shaped groove and the rectangular box culvert; a post-cast strip is arranged in the interval, a construction joint is arranged between the post-cast strip and the rectangular box culvert, the longitudinal steel bars run through the construction joint and embedded into the post-cast strip, an expansion joint is arranged between the post-cast strip and the U-shaped groove, and a first embedded type water stop belt is arranged in the expansion joint; the first embedded type water stop belt longitudinally runs through the expansion joint,the two sides of the first embedded type water stop belt stretch into the post-cast strip and the U-shaped groove respectively, a waterproof material is arranged on the outer surface of the expansionjoint, waterproof layers are laid on the outer surfaces of the U-shaped groove, the expansion joint and the post-cast strip, and the waterproof layers are arranged outside the waterproof material. Itis ensured that the first embedded type water stop belt is tightly combined with the U-shaped groove and the post-cast strip, the waterproof material and the waterproof layers are arranged on the outer surface of the expansion joint, and the better waterproof effect is achieved.