As　the　development　of　wireless　network　and　3rd　generation　communication,　LBS　will　have　broad　application　prospects.　At　the　same　time,　CGML　spatial　data　is　evolving　as　the　transmission　and　exchange　standard　of　mobile　spatial　data　because　of　its　compression　and　rich　information.　Therefore,　a　mobile　cache　strategy　of　CGML　spatial　data　is　proposed.　In　the　strategy,　firstly,　the　basic　and　expand　query　boxes　are　generated　in　the　center　of　terminal＇s　location.　And　then,　the　cartographic　data　received　in　the　basic　box　is　formed　into　CGML　file　Finally,　the　received　data　in　the　expand　box　is　added　to　the　built　CGML　file,　which　is　used　to　follow-up　operation　of　cartography.