The chimeric gene of ACTH(4-10) with GDNF was constructed by PCR amplification. The fused gene was inserted into the expression vector pET-28a(+) and expressed in E.coli. with a level of 30% of the total bacterial proteins. The expressed product was purified by Ni²⁺-NTA resin, up to 85% purity. The results of activity assays showed that the chimeric protein could significantly promote the survival of spinal cord neurons and had a higher neurotrophic activity than ACTH(4-10) and GDNF respectively.