Aquaporin 8 (AQP8) may be involved in cytoplasmic condensation and fluid formation in the vas deferens during the process of spermiogenesis. In the present study, using reverse transcription polymerase chain reaction (RT-PCR) combined with DNA sequencing technology, the splice isoforms of AQP8 post-transcriptionally formed by alternative splicing in porcine testis at various developmental stages were analysed, and the differences in the amino acid sequences encoded by the splice isoforms were compared. The results showed that a total of three splice isoforms of AQP8 mRNA, including full-length mRNA, were produced via alternative splicing in porcine testes at the four developmental stages. Because the number of bases removed during splicing was not an integer multiple of 3, the amino acid sequence and protein structure of AQP8 were significantly altered after alternative splicing.