This paper aims to propose a complex digital watermarking algorithm based on NSCT-DWT-SVD so as to achieve the concealed embedding of watermark information and improve the robustness of the watermark. First, Arnold scrambling was carried out for watermark information. NSCT was carried out for carrier images and then WT (wavelet transform) was conducted for the produced frequency sub-bands with the same size of original carrier image. Second, SVD decomposition was made for the low-frequency part after WT. After the strength of embedding was determined, watermark information was superimposed on the singular value matrix to achieve the watermark embedding. According to the simulation experiment, the algorithm met the concealment of watermark information while guaranteeing the amount of watermark information embedding. PSNR value reached over 30 dB and NC value at 1. Meanwhile, the algorithm had stronger robust against compression, filtering and cropping attack. NC value reached over 0.92. The algorithm still extracted clearer watermark images against spin attack. In conclusion, the algorithm meets the requirements of digital watermarking technology for the invisibility and robustness. It can play a role of copyright protection in the digital products.