According to the published nucleotide sequences,CP gene of barley yellow dwarf virus PAV(BYDV-PAV) was synthesized by reverse transcription polymerase chain reaction(RT-PCR).The reporter gene GFP was put to the downstream of whole CP gene sequence of BYDV-PAV after double enzyme digestion,PCR identification and sequencing.The green fluorescence protein expression system of coat protein of BYDV-PAV was successfully constructed and expressed in Escherichia coli BL21(DE3)plysS.The expression product was confirmed by SDS-PAGE,Western blot analysis and fluorescence microscope.The fusion gene CP-GFP was expressed in the range of 15-22℃,but could not be expressed at 23-37℃.The results provided a base for studying on BYDV-PAV movement in aphid further.