A hydraulic data center is an important infrastructure for in-depth development and utilization of hydraulic information and information share. Hydraulic database access middleware is capable of integrating various heterogeneous hydraulic data sources and providing efficient, transparent data access for users. Nowadays it has become a hot research topic to study data access middleware technology, that can adapt to open, dynamic, and changing Internet environment to guarantee the quality of system service. Reflection enables programs to be accessible, dynamic, detect and modify their own status or behaviors. The paper proposes a reflective database middleware object model with the integration of reflection and database access middleware technology. The reflection is realized by creating an interactive mechanism between base-level functional entities and meta-level. A reflected Middleware Model (ReMM) is also created based on J2EE architecture. Finally the dynamic re-configuration is implemented according to quality parameter changes of service.