The　relationship　between　informatization　and　economic　development　is　very　close.　Informatization　can　promote　rapid　economic　growth.　Conversely,　more　economic　development　creates　favorable　conditions　for　the　development　of　informatization.　Over　the　past　10　years,　Beijing＇s　economy　has　shown　a　sustained　and　stable　growth,　which　is　related　to　the　role　of　informatization　and　its　support.　In　this　paper,　Beijing＇s　informatization　level　was　first　measured　using　related　statistical　data　of　Beijing　(1998-2006).　Second,　the　correlation　between　the　urban　informatization　level　and　the　economic　growth　level　was　analyzed　by　the　Regression　Analysis　Method.　The　result　shows　that　the　development　of　informatization　had　greatly　promoted　economic　growth.　Third,　each　factor　contributing　to　Beijing＇s　economic　growth　was　analyzed　by　the　improved　C-D　Model;　this　analysis　indicates　that　information　had　become　＂the　first　major　production　factor＂　affecting　the　economic　development　of　Beijing;　the　quality　of　laborers　should　be　given　attention　in　labor＇s　input;　and　the　influence　of　other　factors　except　labor,　capital　and　information　can　not　be　ignored.