Bougainvillea spectabilis Willd., whose bracts are colorful and petallike, has been widely used in landscape gardening. In order to further understand the evolutionary mechanism of petallike bracts, we used RNAseq technology to sequence transcritomes in bracts and leaves, respectively, and compared the bracts and leaves at the level of gene expression. In total, 55 782 Unigenes with an average length of 1 003.79 bp and an N50 of 1 402 bp were de novo assembled from 54.48 M bidirectional clean reads of 150 bp in length. There were 30 874 Unigenes successfully annotated to the public database, of which 12 631 Unigenes can be annotated to Gene Ontology. Differential expression analysis identified a total of 456 differentially expressed genes (DEGs) between bract and leaf. The GO enrichment analysis and KEGG enrichment analysis of differentially expressed genes in different tissues showed that: (1) the DEGS highly expressed in bracts contained flavonoidrelated genes, a key enzyme in flower color synthesis (DODA), and genes related to the development of petals; (2) The DEGs highly expressed in leaves were mainly involved in photosynthesis.