Abstract: Bascd on the partitions generated from the equivalence relations, the concept of hybrid multigranulation space was proposed to study the multigranulation space with both disjunction and conjunction. 13y using the partitions in hy- brid multigranulation space, the target concept was approximated and then the concept of hybrid multigranulation rough about hybrid set was proposed. Not only the basic properties multigranulation rough set were explored, but also it was proven that hybrid multigranulation rough set is a generalization of both optimistic and pessimistic multigranulation sets.

Key words: Multigranulation rough set, Hybrid multigranulation space, Hybrid multigranulation rough set