Image　watermarking　capacity　is　an　evaluation　of　how　much　information　can　be　hidden　in　a　digital　image,　Research　of　watermarking　capacity　study　how　to　transmit　more　watermark　information.　In　watermarking　schemes,　image　is　considered　as　a　communication　channel　to　transmit　messages.　Watermark　power　should　be　constrained　according　to　the　content　of　image.　In　this　paper,　we　analysis　shortages　of　some　previous　watermarking　capacity　methods　and　presents　a　watermarking　capacity　method　using　the　noise　visibility　function,　and　discusses　the　watermarking　capacity　of　blind　watermarking　and　non-blind　watermarking.