The　riddled　basin　of　the　chaotic　synchronized　attractor　in　linear　coupled　standard　tent　maps　is　studied　and　proved.　The　notion　of　riddled　factor　is　presented.　According　to　it,　the　critical　value　of　the　coupling　at　which　locally-globally　bifurcation　occurs　is　found　and　the　analytical　expression　of　transverse　Lyapunov　exponent　is　also　revised.　It　is　shown　that　in　chaotic　synchronization　the　riddled　basin　plays　an　important　role.