Abstract: Samples of Agaricus bisporus As2796 fruiting bodies in 4 developmental stages were collected for transcriptome sequencing. After aligned with the reference genome sequence of the mushroom, 9 207 transcripts were identified. Among them, 393 were new genes with 164 being functionally annotated. The expression level of the genes was analyzed to differentiate the samples. The alignments showed an overlapping of 316 differentially expressed genes between the primordium and the 3 other developmental stages. An analysis and function evaluation on these genes were performed for further study on the growth and development of A. bisporus fruiting body.