Abstract: The coat protein gene of a Chinese isolate of cucurbit chlorotic yellows virus was amplified by RTPCR. Sequence analysis showed that the cp gene was 753 bp, encoding 250 amino acid residues and exhibited high sequence similarities (over 95%) with all the CCYV reported in GenBank. The CCYV cp gene was cloned into the prokaryotic expression vector pET32a(+ ), then transformed into Escherichia coli BL21(DE3), and subsequently induced by IPTG. It was shown that the recombinant cp gene was expressed with the molecular weight of 46 kDa with 6-His tag by SDS-PAGE and Western blotting analysis. Antiserum was prepared after the rabbits were immunized with purified recombinant CCYV coat protein. Results showed that the antiserum specifically detected against CCYV in infected melon leaves by indirect enzyme-linked immunosorbent assay (ID-ELISA).