Disclosed is a method for improving folding efficiency and solubility of a target protein linked to a RNA-binding protein by using RNA molecule as a molecular chaperone, wherein the RNA molecule interacts with the RNA-binding protein. More particularly, the present invention discloses method for improving folding efficiency and solubility of a target protein by transformation of a host cell with a expression vector comprising a polynucleotide encoding the target protein linked to an RNA-binding protein; culturing the transformed host cell in an appropriate culture medium under the condition that an RNA molecule either resident inside the host cell or provided by cotransformation of the host cell with polynucleotide encoding the RNA molecule interacts with the RNA-binding protein; and purifying the soluble protein from host cell lysate. The method of the present invention is very useful for production of soluble proteins for therapeutic, prophylactic and diagnostic applications.