The study on the procedure of applicating bacteriophage (or phage) to prevent rice bacterial grain rot caused by Burkholderia glumae was conducted in the greenhouse conditions. The first experiment investigated the effect of different phage titers (i.e. 10⁵ PFU/mL, 10⁶ PFU/mL, 10⁷ PFU/mL, 10⁸ PFU/mL) in controlling bacterial grain rot of rice. The results showed that all four titers gave disease reduction with different levels, among these were the titer of 10⁸PFU/mL expressed highest efficacy in disease reduction with the lowest percentage of infected grains compared to the rest treatments. The second experiment examined the effect of phage application times (i.e. spraying phage at 2 hours before pathogen inoculation, 2 hours before and 5 days after pathogen inoculation, and 5 days after pathogen inoculation) in suppressing bacterial grain rot disease. The results found that two treatments (i.e. one time spraying at 2 hours before pathogen inoculation, and two times spraying at 2 hours before and 5 days after pathogen inoculation) expressed high efficacy in reduction of grain rot disease through percentage of infected grains and improved yield parameter regarding rate of filled grains.