Abstract: In order to develop a microbial agent that can prevent and cure continuous cropping obstacles in apple，six common pathogens were tested，and the roots of healthy apple in continuous cropping orchard were used as materials to screen the antagonistic endophytes. Two strains SRB-1 andSRB-11 with significant antagonism were identified as Bacillus subtilis and Bacillus mojavensis，respectively. The pot experiment was carried out to verify the effect of SRB-1 and SRB-11 on the continuous cropping obstacle of apple. The results of pot experiment showed that the application of bacterium fertilizer in soil significantly promoted the growth of Malus hupehensis seedlings under continuous cropping conditions and had a good effect on the soil. Compared with control treatment，the application of bacterium fertilizer significantly increased plant height，basal diameter，fresh weight and dry weight，increased the activity of superoxide dismutase（SOD），catalase（CAT）and peroxidase（POD）in the roots of Malus hupehensis by 65%，51% and 230%，respectively. Meanwhile，the activities of invertase，urease，phosphatase and catalase in soil were significantly increased by 132%，57%，82% and 146%，respectively. The above results indicate that the microbial agents prepared by the endogenous antagonistic SRB-1 and SRB-11 screened in this study have a certain preventive effect on apple continuous cropping disorders.

Key words: Malus hupehensis, continuous cropping obstacle, endophyte antagonism, promoting effect, soil enzyme activity, root enzyme activity