Abstract：Bottleneck problems such as soil nutrients exhaustion,soil fungal diseases prevalent,soil structure degradation,low production and quality of water melon,already severely restricted Gravel-covered watermelon industry in middle arid area of Ningxia. This experiment is based on the production practice of Grovel-covered Watermellon in Ningxia. Separation of Fusarium oxysporum f. sp. niveum from the incidence of serious disease of watermelon,and the control effect of Fusarium wilt was screened from different types of healthy soil,the effect of antagonistic strain on disease control and classification and identification were studied. During dilution plate method screened with antagonism of antagonistic bacteria to target. Through the screening of 8 strains of bacteria which have antagonistic effect on the target,the screening test was carried out. After data analysis,G-1 inhibitory rate is maximum,and there was a significant difference compared with other treatments,it was screened on the target antagonistic strongest antagonistic to the G-1. According to its morphological,physiological and biochemical characteristics and 16 S r DNA sequence homology analysis can determine the antagonistic strain G-1 is Bacillus atrophaeus.

Keyword：arid area soil;watermelon fusarium wilt;antagonist;Fusarium oxysproum;