A rule-based system must satisfy stringent timing con-straints when applied to a real-time environment. The most critical performance factor in the implementation of a pro-duction system is the condition-testing algorithm. We show an approach designed to reduce the response time of rule-based expert systems by reducing the matching time based on RETE.There are two steps in the method we propose: The first makes an index structure of the tokens to reduce the β-node-level join candidates. The second chooses the highest time tag for certain β-nodes to reduce the size of the β-memory and to keep the strategy of the RETE network. These steps reduce the amount of combinatorial match that is problem-atical in a real-time production system application.