Abstract: Here we constructed a retroviral vector mediated mammalian cell expression system of the capsid precursor protein of foot-and-mouth disease virus (FMDV). The recombinant retroviral vector pBABEpuro-P1-2A-EGFP was constructed by inserting capsid precursor protein gene （P1） of FMDV and enhance green fluorescent protein gene(EGFP) into pBABEpuro by turns. Both the recombinant retroviral vector and the pVSV-G plasmid were cotransfected into packaging cell GP2-293 by liposomemediated transduction. And then, the pseudovirus were produced. The pseudovirus infected BHK-21 cells and resistance cells were screened by puromycin-resistant. The green fluorescent protein were observed under fluorescence microscope. The expression of capsid precursor protein gene of FMDV was detected by indirect immunofluorescence assay. The recombinant retroviral vector pBABEpuro-P1.2A-EGFP was constructed successfully. The capsid precursor protein of FMDV and green fluorescent protein could express in BHK-21 cells. The mammalian cell expression system of the capsid precursor protein of FMDV had been constructed successfully, which laid a foundation of development of FMDV subunit vaccine.