Boule gene, one of the DAZ (Deleted in Azoospermia) gene family members, is specifically expressed in animal germ cells. In mammals, the boule null caused spermatogenic failure, leading to male infertility, while the loss of boule in invertebrate, such as Caenorhabditis elegans resulted in female sterility due to a failure of oogenesis. Turtles are considered as a link between the high and low vertebrates, however, the molecular mechanisms behind germ cell development in reptile including turtles remain largely unclear. In this study, we used the Chinese Soft-shell Turtle (Pelodiscus sinensis) as a model to reveal the mechanisms under germ cell differentiation in turtles. Firstly, we cloned a turtle boule cDNA fragment of 1 005 bp, containing a 3′ untranslated region (UTR) of 57 bp and an open reading frame (ORF) of 948 bp, encoding 315 amino acid residues (Fig. 1). The predicted turtle Boule is maximally 92% identical to that of Chelonia mydas, 83% to that of mouse, 53% to that of Drosophila melanogaster and 42% to that of Oryzias latipes (Fig. 2). The reverse transcription quantitative real-time PCR (RT-qPCR) showed that boule transcript of P. sinensis was abundantly expressed in adult ovary and testis but barely in all the somatic tissues examined in this study (Fig. 4). Chemical in situ hybridization revealed that the boule mRNA of P. sinensis was exclusively expressed in germ cells but absent in somatic cells, and displayed dynamic expression patterns in germ cells during gametogenesis (Fig. 5 & 6). In testis, the boule mRNA signals were strongly dispersed in cytoplasm of primary spermatocytes and weakly in spermatogonia and secondary spermatocyte, hardly detected in spermatids and spermatozoa (Fig. 5). In ovary, the boule mRNA signals were strongly dispersed in cytoplasm of oocytes at early stages. Subsequently, the signals were concentrated in the perinuclear area of growing oocytes and weakened gradually with the growth of oocytes (Fig. 6). Therefore, our findings indicated that boule gene might play an important role in germ cell meiosis in Pelodiscus sinensis, which shed new insight into understanding the functions of boule gene during germ cell differentiation in vertebrates.