In a data protection field, a method for storing data in a data deduplication system, comprising: obtaining data chunks achieved from data deduplication; assigning the data chunks to at least one group; recording grouping information of the data chunks; with respect to each group, calculating parity data chunks based on data chunks in the group, where the parity data chunks are used for, in response to a data chunk in the group being damaged, causing the damaged data chunk to be recovered on the basis of other data chunks in the group and parity data chunks of the group; and storing the calculated parity data chunks. Also provided is an apparatus for storing data and a data deduplication system. The technical solution provided herein facilitates occupying as little physical storage space as possible while reducing the risk of the spread of data loss caused by the data deduplication technology.