Cecropins are a family of antibacterial peptides synthesized in insects as a response to a bacterial infection. Two primers were designed according to cecropin B gene from Spodoptera litura and were used to PCR. As the result, two new cecropin genes, named cecD1 and cecD, were obtained, which encoded identical preprocecropin D. There was 2 amino acid residues difference between the mature peptide of preprocecropin D and that of cecropin B from S. litura. Two introns, 568 bp and 377 bp long, were found in cecD1 and cecD2, respectively, both having the same 5′and 3′splicing sites. The A+T content was 59.7% in cecD1 intron and 69.8% in cecD2 intron, conforming to the high A+T content characteristics of most eukaryotic introns.