The invention discloses a sectional oblique cofferdam structure in a moon pool region. The sectional oblique cofferdam structure is characterized in that an upper-section cofferdam (2) and a lower-section cofferdam (3) are arranged on bulkheads between a moon pool (4) and a liquid tank (1), the widths of the upper-section cofferdam (2) and the lower-section cofferdam (3) are identical to the width of the moon pool (4), the upper-section cofferdam (2) is positioned on the inner side of the bulkhead of the liquid tank (1), and the lower-section cofferdam (3) is positioned on the outer side of the bulkhead of the liquid tank (1) and is arranged in the moon pool (4). A cofferdam in a design comprises an upper section and a lower section, the upper-section cofferdam is provided with an oblique bottom and is positioned in the liquid tank, the lower-section cofferdam is provided with an oblique top and is positioned in the moon pool. Oblique angles of the cofferdam cannot be smaller than 30 degrees or larger than 60 degrees because of construction requirements. The sectional oblique cofferdam structure has the advantages that parts of the cofferdam in the liquid tank are outwardly arranged on the basis that requirements on normal operation of marine engineering equipment are met, accordingly, influence of the moon pool on sailing can be reasonably reduced, spaces of the moon pool and the liquid tank can be reasonably optimized, and the sailing performance of ships can be improved.