Abstract: The present application relates to a fusion protein and use thereof. The fusion protein comprises RdCVF and a signal peptide, wherein the signal peptide is an amino acid sequence set forth in any one of SEQ ID NOs: 27-31 and 33. The present application also relates to an isolated nucleic acid molecule comprising a) a polynucleotide encoding RdCVF and b) a polynucleotide encoding a signal peptide. The present application also provides a vector, a cell, and a pharmaceutical composition containing the nucleic acid molecule, as well as medical use thereof. The fusion protein and/or isolated nucleic acid molecule described herein can effectively increase the secretion of RdCVF.