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The present study investigates the effects of a dried Bacillus subtilis culture (DBSC) on the performance and egg qualities of layers. Nine hundred and sixty 25-week-old Lohmann Brown layers were randomly divided into 5 groups with 192 layers in each group. Layers in group one were fed a control diet. The second group received the control diet to which 20mg/kg zinc bacitracin and 4mg/kg colistinsulfate were added. Layers in the other three treatment groups were fed the control diet plus 500mg/kg, 1000mg/kg, or, 1500mg/kg B. subtilis culture, respectively. The results showed improvements in egg production, and in feed consumption and efficiency (P<0.05) of layers when 500mg/kg B. subtilis culture was added to the diets. The results also showed other improvements in this group, including increases in egg shell thickness, yolk color, and Haugh unit , and decreases in yolk cholesterol concentration (P<0.05). However, excessive doses of B. subtilis culture did not improve the performance of layers.