Safety is the most basic requirements for probiotics. The safety of newly selected probiotic strainsmust be totally evaluated before its commercial production. In this paper, Bacillus subtilis JAASB4, a newly separated and identified strain, was assessed via the oral acute toxicity and translocation. The results showed that there wasno obvious abnormal impact on indicators of mice, such as weight, behavior, activity, diet, stool and other signs ofdirty body. There were no significant difference in liver, spleen ratio between the experimental group and controlgroup. There is no strain translocation also. Therefore, initial proof showed that Bacillus subtilis JAASB4 was safe.