The present invention relates to a method for producing recombinant soluble flag-tagged single chain variable fragment (scfv) targeting cucumber mosaic virus (cmv) coat protein. The soluble flag-tagged single chain variable fragment (scfv) antibody produced according to the present invention is utilized to bypass tedious and time-consuming hybridoma development. Meanwhile, it is now possible to produce the desired functional antibodies in large amounts in a short period. In addition the scfv produced may be used for producing cmv-resistant transgenic plant.