The analysis of satellite user requirements is the first and critical step to plan and manufacture meteorological satellites. To outline the frame of global meteorological satellites in the 21st century, WMO and CEOS began to collect user requirement information and establish global user databases for earth observing satellites from 1996, and devised the Rolling Requirements Review (RRR) process methods. The RRR process method and parts of the WMO/CEOS user database are introduced. The emphasis is put on the presentation and review of the establishing of satellite user requirements and its application in the quantitative evaluation of satellite observing capacity, to found a base for establishing the Chinese meteorological satellite user requirement database.