Using rape and rice as explants,the colonization range,promotion of growth and aphid bioassay of the endophytic bacterium YY-23 and SJ-10 were tested in laboratory.The results showed that the two strains were able to colonize in rape,rice,wheat,maize,Chinese kale,navet,etc.Rape seeds were dipped for 24 h with YY-23 and SJ-10,then sowed.20 days later,the fresh weight of rape plants treated by YY-23 and SJ-10 was increased by 113.5% and 52.5%,respectively.The survival rate of aphid in SJ-10 group was lower than CK on the sixth day,the difference was significant (P<0.05).However,YY-23 expressed no resistance to aphid.Therefore,the two strains could stably colonize and promote growth of plant.SJ-10 had insecticidal effect on aphid.