The invention provides a method and a system for optimizing data query performance. The method comprises: introducing a distributed memory database outside a relational database; establishing a synchronous modification mechanism between the relational database and the distributed memory database. The technical scheme introduces the distributed memory database out of the relational database, and establishes the synchronous modification mechanism to ensure consistency of data, thereby reducing the number of times of reading from and writing into a traditional relational database, so that data query speed is greatly improved, and computing speed is not affected in multi-user concurrence. The method and the system are easy to use and have wide adaptability.