Abstract: To obtain high density bacterial fertilizer, the liquid fermentation conditions of Bacillus atrophaeus were optimized by single factor experiments. The results showed that the optimal culture conditions were temperature of 32℃, initial p H of7.0, medium volume of 50 m L/250 m L flask, inoculation amount of 2% and incubation time of 24 h. The results could provide basic data for production of Bacillus atrophaeus bacterial fertilizer for agricultural application.