The transcriptome of triangle sail mussel Hyriopsis cumingii (Lea) using Illumina paired-end sequencing technology was conducted and analyzed. Equal quantities of total RNA isolated from six tissues, including gonads, hepatopancreas, foot, mantel, gills and adductor muscles, were pooled to construct a cDNA library. A total of 58.09 million clean reads with 98.48 % Q20 bases were generated. Clustering and assembly of these reads produced a non-redundant set of 92,347 unigenes with an average length of 1,150.61 bp. 11,174 unigenes were involved in the molecular function, cellular component and biological process categories by GO (Gene Ontology) analysis. Potential genes and their functions were predicted by KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway mapping and COG (Cluster of Orthologous Groups of proteins) analysis. More than 8 putative genes of interest involved in sex determination/differentiation were identified. Furthermore, 8,014 SSRs and 38,288 SNPs were identified in this transcriptome dataset.