The APAatlas refers to "Alternative PolyAdenylation atlas in human tissues". Widespread alternative polyadenylation (APA) occurs during cell proliferation and differentiation, exhibits strong tissue specificity. Recent studies have highlighted the important role of APA in transcription regulation. Here we systematically characterize APA profile in 9,475 samples across 53 human tissues from Genotype-Tissue Expression (GTEx) project with two algorisms, and analyzed the association between APA events with traits and mRNA expression. These APA events may uncover novel mechanisms for the transcription regulation, development of tissues and phenotypes.