The invention discloses an extendible repeated data detection method, belongs to the technical field of computer storage, and solves the problem that in the existing repeated data detecting method, the storage capacity cannot be efficiently extended, so as to meet the requirements of the current situation that the storage demand increases and repeatedly deleted systems need upgrading and updating. The extendible repeated data detection method comprises the following steps: partitioning processing, fingerprint extraction, retrieving of Bloom filters, retrieving of fingerprint subset table, judgment of unfulfilled Bloom filters, new fingerprint marking, judgment of Bloom filter quantity, and extending of Bloom filter array. In the invention, the Bloom filter array is used to retrieve the fingerprint data, so as to quickly locate the retrieval range, improve the retrieval efficiency and realize detection on the repeated data; the extendible repeated data detection method is high in expansibility and querying performance, can support element location and control the misjudgment rate, and further can effectively reduce the memory overhead. The Bloom filter array is composed of a series of isomorphic Bloom filters, so that once the misjudgment rate epsilon' and the pre-established retrieving fingerprint total quantity nmax are provided, the quantity of the required Bloom filters and the number of the hush functions can be worked out.