Recombinant human β nerve growth factor (rhβ-NGF) in insect cells was expressed, the expressed product was purified and its biol. activity was detected. Recombinant plasmid Bacmid+[rhβ-NGF] was constructed and transfected to insect cell line Sf9 in mediation of liposome cellfection II. Sf9 cells were repeatedly infected with the supernatant of transfected cells, of which the culture supernatant containing target protein was collected in a large quantity. The rhβ-NGF was purified by ion exchange and mol. sieve chromatog., identified by SDSPAGE and Western blot and determined for biol. activity by chick embryo dorsal root nervous ganglion culture method. Restriction anal. and sequencing proved that recombinant plasmid Bacmid +[rhβ-NGF] was constructed correctly. The rhβ-NGF was expressed in Sf9 cells infected with recombinant virus, which showed a single band with relative mol. mass of about 14200 on SDS-PAGE profile and reached a purity of more than 98% after purification The expressed protein showed specific binding to rabbit anti-human monoclonal antibody against NGF and stimulated the growth of nerve ganglion process, of which the specific activity was about 600000 AU/mg. The rhβ-NGF with biol. activity was expressed successfully in insect cells, which laid a foundation of preparation of rhβ-NGF in a large quantity.