A strategy was developed to express Cecropin AD and BuforinⅡusing the lactose self-induced system in recombinant Escherichia coli BL21(DE3), harboring plasmid pET-Trx-CAD-BuforinⅡ. First, studies were done in LB culture to detect the effects of lactose concentration, induction-timing and induction-time on target protein expression. Then, lactose self-induced system was constructed according to the “carbon catabolite repression” principle. The protein expression process was divided into two phases: the first phase of cell growth, E. coli grew with glucose as carbon source. At this time, lactose could not enter into the cell to induce protein expression. The second phase of protein expression, E. coli grew using “main carbon source” after glucose depleted. Meanwhile, lactose enter into the cell to induce protein expression. The target protein content reached to 45.2% of total protein using the optimized “glucose xylose” self-induced system.