High-throughput mass spectrometry and antibody-based experiments have begun to produce a large amount of proteomic data sets. Chromosome-based visualization of these data sets and their annotations can help effectively integrate, organize, and analyze them. Therefore, we developed a web-based, user-friendly Chromosome-Assembled human Proteome browsER (CAPER). To display proteomic data sets and related annotations comprehensively, CAPER employs two distinct visualization strategies: track-view for the sequence/site information and the correspondence between proteome, transcriptome, genome, and chromosome and heatmap-view for the qualitative and quantitative functional annotations. CAPER supports data browsing at multiple scales through Google Map-like smooth navigation, zooming, and positioning with chromosomes as the reference coordinate. Both track-view and heatmap-view can mutually switch, providing a high-quality user interface. Taken together, CAPER will greatly facilitate the complete annotation and functional interpretation of the human genome by proteomic approaches, thereby making a significant contribution to the Chromosome-Centric Human Proteome Project and even the human physiology/pathology research. CAPER can be accessed at http://www.bprc.ac.cn/CAPE .