Abstract: A peer-to-peer based secondary key search method and system for cluster databases is disclosed. A cluster database has a plurality of storage nodes and each storage node is assigned with a node number and stores a plurality of records. A search term input means couples to the plurality of storage nodes for retrieving a record at a storage node. The search term input means calculates a first node number based on a hash function of a secondary key, queries the first storage node with the secondary key for retrieving a corresponding primary key, calculates a second node number based on a hash function of the primary key, and then queries the second storage node with the primary key for retrieving a corresponding record.