In order to study the expression and the feasibility of scaled production of neuropeptide in the routine expression system such as E.coli with the pituitary adenylate cyclase activating polypeptide(PACAP) as an example, the following experiments were carried out. First, on the basis of the reported amino acid sequence of PACAP, DNA sequence of PACAP was deduced and six partially complementary oligonucleotide fragments were designed. The coding region of PACAP was obtained by renaturing the DNA fragments and ligation and identified by DNA sequencing. The coding region of PACAP was cloned into plasmid pGEX-4T-3 and transformed into E.coli BL21(DE3). An expression strain BLPACAP was selected. SDS-PAGE analysis revealed that the GST-PACAP fusion protein was highly expressed and accumulated to about 30% of the total bacterial proteins. By affinity chromatography, up to 90% GST-PACAP was purified by one step from bacterial lysate. The purified protein could promote neurite outgrowth of PC12 cells and the survival of spinal cord neurons.