The fibroin promoter can stably express foreign gene in lepidopteran cells. Total RNA was extracted from the gland of silkworm,Antheraea pernyi and the transcription initiation site of fibroin gene ofA. pernyi was identified by RNA ligase mediated rapid amplification of cDNA ends (RLM-RACE). The expression vector (pGFP-N2/Fib) was constructed by use of replacing the CMV promoter with the fibroin promoter. The results of visual screening under a fluorescent inverted microscope and Western blot analysis indicated that the GFP gene was expressed in the primary cells of ovary origins fromA. pernyi.