In this paper, we propose a spectrum database for storing received signal power distribution using clustering for reducing the types of registered distribution. In order to estimate radio environment, a measurement-based spectrum database (MSD) is considered and the distribution of the received signal is important for keeping the outage probability of the system performance. However, if we consider the database stores all of the distributions corresponding to each location, the amount of stored data becomes very large. In order to construct a practical database, the amount of stored data should be reduced while the highly estimation accuracy is maintained. Therefore, in this paper, the database firstly estimates the received signal power distribution in each location. Then, the similar distributions are integrated by clustering so the amount of stored data can be reduced. We evaluated the accuracy of the clustering and showed that similar distributions can be accurately clustered. In addition. we performed the transmit power control (TPC) by using the clustered distributions. The results showed that the permissible outage probability can be guaranteed while the amount of stored data can be drastically reduced.