Decentralized tuple space is an e®ective paradigm for distributed collaborative applications since its loose decoupling, availability and °exibility in system's organization. However, there are very few research results on its replication and consistency. This paper presents a decentralized tuple space model to enable tuple update by creating loose update links among decentralized Tuple space nodes. Besides, tuples are grouped with tuple types, the unit of being applied a replication policy, which con- trols the distribution of replicas. The model is simulated by Desmo-J. The experiments show that applying di®er- entiate replication policies used for di®erent purposes is absolutely necessary, because no single policy is suitable under all use patterns.