For watermark algorithm of the same kind, the values assigned to some factors could bring substantial influence to the watermarking system. This article primarily analyzes these factors which affect the performance of the watermarking system through the quality of image perception and robustness, provides specific experimental data, and explains the importance of the assignment of these values in algorithm design. This article employs two kinds of watermark information carriers which can precisely explain the problem and evaluate the performance of the watermarking system.