Abstract: Our purpose of this work is to obtain the partial coding region sequences of CATSPER3 gene from Banna Mini-pig Inbred Line（BMIL），and to analyze the amino acid sequence and homology comparison among different species by bioinformatics. We used boar testis material of BMIL to extract RNA，RT-PCR to amplify the coding sequence of CATSPER3 gene，and online analysis software to analyze the bioinformatics. Bioinformatics analysis showed that the protein molecular weight of deduced amino acid sequence was 19.397 3 kD and theoretical isoelectric point was 5.05. Regarding the composition of amino acid，there were 24 acidic amino acids（Asp and Glu）；and there were 16 alkaline amino acid（Lys+Arg）；among them the leucine（Leu）accounted for 13.3%，valine（Val）9.6%，threonine（Thr）9.0%，phenylalanine（Phe）8.4%，glutamate（Glu）7.2%，aspartic acid（Asp）7.2%，and their contents were high. Compared with ordinary pig，the nucleotide similarity was the highest，however，lower with that of goat. Molecular phylogenetic tree showed that inbred pig and non-inbred pig clustered in the same branch，i.e.，their genetic relationship was close，while far from goat and sheep.

Key words: Banna Mini-pig Inbred Line, CATSPER3 gene, phylogenetic analysis