Two strategies were adopted to enhance the water-soluble prokaryotic expression of potato leafloll virus CP gene. Firstly， 5 chaperone-expression plasmids were transformed into the recombinant E. coli strain TOP10（pBAD-LRCP）， respectively. Restriction endonuclease digestion identification indicated that the yielding trans-formants contained both pBAD-LRCP and chaperone plasmid. After induction with L-arabinose or L-arabinose and tetracycline， PLRV-CP  gene and chaperone gene were both expressed， and recombinant PLRV-CP  band was observed in SDS-PAGE pattern of the supernatant protein from the trans-formanat， water-soluble expression of PLRV-CP  gene was enhanced by the presence of chaperone protein. Secondly， PLRV-CP  gene was inserted into prokaryotic expression vector pCold Ⅰ in direct orientation and cold-shock expression vector of PLRV-CP  gene named pCold-LRCP was constructed. The recombinant strain BL21（ pCold-LRCP） was cultured at 15 ℃ for 24 hours to induce the expression of PLRV-CP  gene. Obvious PLRV-CP  band was found in SDSPAGE analysis of water-soluble protein of the recombinant strain. The results showed that chaperone and coldshock protein gene（ cspA） promoter both enhanced water-soluble expression of PLRV-CP  gene， and the soluble
expression level of cspA promoter was higher than that of the chaperones.