The utility model discloses a floating box platform for over-water construction. The floating box platform is characterized by comprising a platform faceplate and handrails, and further comprising a plurality of section steels, hollow sealing steel pipe floating boxes and steel pipe piles, wherein the handrails are fixed to the periphery of the platform faceplate; the section steels are transversely fixed under the platform faceplate at intervals; the sealing steel pipe floating boxes are longitudinally fixed under the section steels in parallel; the steel pipe piles are arranged on the four corners of the platform faceplate in such a manner that the upper ends penetrate out of the platform faceplate and the lower ends are inserted into water until being in contact with rock face of earth surface; at the parts where the steel pipe piles are intersect with the section steels, two anchoring steel clamping plates are arranged to be fixedly connected with the sealing steel pipe floating boxes at the two ends of the platform faceplate; the two sides of the platform faceplate are linked through limiting bolts and the steel pipe piles. The platform is good in stability, and can be moved entirely and anchored fast; besides, the structure of the platform is simple in structure, and easy to operate; moreover, the cost is greatly reduced; compared with the conventional over-water support platform, the platform is more scientific in the aspects of work efficiency, economy and environmental protection, and can be applied to over-water construction.