The current implementation of BGP protocol has a variety of vulnerabilities and weakness. BGP monitors are designed to monitor and analyze BGP behaviors. To monitor a router?s historical behavior, we need to collect its route tables at different times and store them into database. Because current BGP table size exceeds 100 000, it seems to be a heavy burden to deal with so many route tables of different times. In this paper, we propose a systematic approach for compression within and among route tables for BGP monitor?s Database & Analyzer. With the help of our approach, our compressed database can join all these tables together as well as facilitate joint time-domain analyzing on them. Because all compression is not based on entries but on tables, no decompression is needed during the query process. The querying efficiency doesn?t decrease significantly with the compression.