Abstract: We studied the physical and chemical properties of antibacterial material of Bacillus subtilis S-16, a good biocontrol agent of sunflower Sclerotinia rot. Results showed that the antibacterial material had a good effect under 20 ℃ for 1 h with inhibition zone 1.72 cm; the activity decreased with the increase of temperature, but still active under 80 ℃ for 1 h with inhibition zone 1.00 cm. The results showed that the antibacterial material was thermally stable. The antibacterial material was resistant against trypsin, chymotrypsin and pepsin treatments. Inhibition zone under ultraviolet irradiation and control were 1.57 cm and 1.85 cm respectively. These result demonstrated that the antibacterial material of S-16 was lipopeptide. The most conducive conditions to produce the antibacterial material were glucose as carbon source, beef extract as nitrogen source, neutral pH with 20—40 ℃ temperature.