Plant diseases are caused mainly by fungi, bacteria, virues and nematodes seriously and Pyricularia oryzae is main disease on rice plant, especially rice-seedling stage. Pots and field experiments were carried out to evaluate effects of antagonistic BaciUus against rice blast disease by Pyricularia oryzae in high-yielding rice cultivated on soils of Tra Vinh, Vinh Long and Soc Trang in autumn - winter, 2013 and winter-spring 2013-2014 cropping-seasons. The results showed that two Bacilus subtilis KGT1 and Bacilus
subtilis VLD1 strains have good against ability to Pyricularia oryzae and they were used by mixing bacterial liquid with rice seed (before sowing) and spraying bacterial liquid to rice leaves to limit the development of Pyricularia oryzae on rice plant cultivated in pot and field experiments. Furthermore, yield component and grain yield of rice treating with antagonistic Bacillus subtilis KGT1 and Bacilus subtilis VLD1 strains did. not differ from rice only treating with chemical pesticides significantly. Therefore applying bio-product for rice cultivation, farmers not only received many incomes but also reduced big quantity of chemical pesticides, environmental pollution and this practice increases quality rice, good food and safety to healthy human.