Objective：To study the expression characteristics of Placenta-specific 8 like 1（Plac8l1） in mouse testicular tissue，and to reveal its possible function during spermatogenesis. Methods：The candidate gene Plac8l1 was preliminary screened to be specific ex－pression in testis by bioinformatics methods，and it is speculated that the gene was related to the spermatogenesis. Besides，semi quantitative RT-PCR and real-time quantitative RT-PCR were used to investigate the tissue specificity of plac8l and the temporal and spatial characteristics of the process of spermatogenesis，while in situ hybridization was used to preliminarily study the expression characteristics of Plac8l1 mRNA in the testis of adult mouse. Finally，the subcellular localization was studied and its functional was pre－dicted by constructing PLAC8L1-EGFP recombinant protein particle and bioinformatics analysis. Results：①The results of preliminary bioinformatics showed that Plac8l1 is one of gene for specific transcription. ②Semi-quantitative and quantitative real-time RT-PCR indicated that Plac8l1 only transcript in adult mice testis and epididymis，and testicular expression level was significantly higher than epididymis. ③As the mouse matured，the Plac8l1 transcription level in testis increased gradually. ④RNA in situ hybridization showed that mRNA was mainly positioned in ledig cell and sperm mother cell in mature mouse testis. ⑤Bioinformatics analysis showed that PLAC8L1 also had a function domain similar to the PLAC8 and the over expression of recombinant proteins showed that protein aggregated in the cell membrane. Conclusion：Plac8l1 is a testis specific gene，and is very likely to associate with spermatocyte differ－entiation in the process of spermatogenesis. PLAC8L1 has a cystine which riches in PLAC8 domain，and the domain may mediate PLAC8L1 to aggregate in cell membrane and interact with other protein and play an important role in spermatocyte differentiation.