The invention discloses an OLAP (On Line Analytical Processing) inquiry processing method facing a database and a Hadoop mixing platform. In the method, on the basis of a multicopy fault-tolerance mechanism of a Hadoop, when the OLAP inquiry processing is carried out, firstly, the OLAP inquiry processing is executed on a main working copy and an inquiry processing result is recorded into an aggregation result table of a local database; and when a working node goes wrong, node information of a fault-tolerance copy corresponding to the main working copy is searched by a namenode and a MapReduce task is called to complete the OLAP inquiry processing task on the fault-tolerance copy. According to the invention, a database technology and a Hadoop technology are combined and the storage performance of the database and the high extendibility and high availability of the Hadoop are combined by a mode of double storage engines and double inquiry processing engines; and the database inquiry processing and the MapReduce inquiry processing are integrated in a loosely coupling mode by utilizing a master-slave copy management mechanism so as to not only ensure the high inquiry processing performance, but also ensure the high fault-tolerance performance.