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