Recently,　wavelet　transform　has　been　applied　widely　in　watermarking　research　as　its　excellent　multi-resolution　analysis　property.　Almost　all　previous　works　on　watermarking　capacity　are　realized　in　spatial　domain.　This　paper　proposes　an　adaptive　watermarking　capacity　analysis　method　in　wavelet　domain.　This　paper　also　analyzes　the　relation　between　watermarking　capacity　and　watermarking　detection　bit　error　rate　(BER),　and　derives　the　relation　between　capacity　and　the　limit　of　BER　for　the　first　time.　According　to　the　result　of　our　research,　watermarking　detection　BER　is　mainly　influenced　by　the　watermarking　average　energy　and　watermarking　capacity.　The　BER　rises　with　the　increase　of　watermarking　capacity.