Abstract: We aimed to study the immune stimulating factor IL-2 from the perspective of molecular biology and explore its protein structure. Primer 5.0 was used to design a pair of primers according to the sequence of IL-2 in GenBank.IL-2 gene was amplified and cloned to pGM-T vector, and identified by restriction enzyme, and PCR. Then the nucleotide sequence was analyzed. Bioinformatics software was used to analyze the amino acid sequence, transmembrane domain, phosphorylation sites, and predict the secondary and tertiary structure of IL-2. The results revealed thatIL-2 gene was 430 bp and encoded 143 amino acids. Bioinformatics analysis indicated that IL-2 protein contained 1 serine and 3 threonines, which might become phosphorylation sites of protein kinase. Besides, IL-2 might contain transmembrane domain within sites 5-28. The secondary and tertiary structure prediction results indicated that IL-2 was a hydrophilic protein, and dominated by α-helix, β-turn and random coil at N terminal. The study lays a foundation for the molecular research of IL-2.