Abstract: The coat protein (CP) gene of a potato virus X (PVX-GZ) isolated from potato in Guizhou was cloned and sequenced. The CP gene was 714 bp long and encoded a 237 amino acid residues with a predicted molecular mass of 25.2 ku. Sequence comparison results showed that the nucleotide and deduced amino acids sequences of the gene share homology with 19 reported PVX isolates were 78.6%~97.5% and 84.8%~99.6%, respectively. The highest nucleotide sequence homology (over 97.1%) was reached when compared with the isolated X3 from Holland and UK3 from UK, two representative isolates of PVX strain X3. Consistent results from differential host test revealed that PVX-GZ belonged to strain X3.