The invention provides a partitioned bottom sealing method applied to the technical field of bridge sunk well foundation construction. The partitioned bottom sealing method for a large volume sunk well comprises the following steps of: during partitioned bottom sealing of the large volume sunk well, firstly, arranging a pouring guide tube (3) extending through to the sunk well base (2) near a partition wall (1), then pouring concrete (11) through the pouring guide tube (3) into the sunk well base (2), and plugging the gap between the partition wall (1) and the sunk well base (2) by the concrete (11). By adopting the partitioned bottom sealing method for a large volume sunk well provided by the invention, multiple processes such as sand filling, sand sucking, secondary foundation clearing and the like are reduced compared with a conventional partitioning method, thereby obviously simplifying the construction steps, reducing the labor intensity of construction, improving the efficiency of construction, accurately realizing plugging of the gap between the partition wall and the sunk well foundation base by concrete, and obviously improving the concrete pouring quality of sunk well bottom sealing.