Objectives:Using IE 1 gene promoter of Autograph californica nuclear polyhedrosis virus(AcNPV),a transfer vector with an immediately early gene promoter was constructed.　Methods:Transfer vector pAcPIneo which contains neomycin resistance gene(neo)coding sequence downstream of IE 1-promoter was constructed and cotransfected with the wild type of AcNPV DNA into Sf9 insect cells.Recombinant virus was selected by G418 resistance since the neo gene can be expressed in Sf9 cells.　Results:Northern blot hybridzation with 32　P labeled neo gene fragement as probe showed that the neogene was integrated in plogene of AcNPV genome.　Conclusions:Transfer vector with an immediately early gene promoter of baculovirus was constructed successfully,the neo gene was transcribed from the immediately early phase to the very late phase in infected cells.