This paper describes the necessity of implementing design optimization for the large-scale data table in the database design stage. It introduces the concept and causes of the large-scale data grid table. And for database performance problem caused by the large-scale data table, it proposes design optimization technology of the large-scale data table. On database design stage of equipment condition-based maintenance system, it uses these technology in device status evaluation function as an example. The simulation experiment results show that system performance has been significantly improved after design optimization for the large-scale data table. To provide protection for the subsequent stability of the system, it is also referable for those large-scale data table need to be optimized.