IL-1 beta cDNA was obtained by RT-PCR with the template of the total RNA extracted from leukocytes which was separated from human peripheral blood. 5' and 3' primers were synthesized according to literaturees reported sequence of IL-1 beta. IL-1 beta gene was highly expressed in E. coli and the expression level reached to about 40% of total bacteria proteins. Separation, purification and bioactivity analysis of the expressed products was performed. The purity of the final products reach more than 98%, and the culture solution of EL-4 cells induced by hIL-1 beta can promote the proliferation of CTLL-2 cells obviously.