Abstract: A dynamic gastric digestion model was used to study the effects of Bacillus subtilis on the O/W and W/O soy protein-phospholipid composite emulsions during enzymatic hydrolysis, taking turbidity, particle size, zeta potential of emulsion and its microscopic observations as indicators. It was found that the turbidity of Bacillus subtilis-free O/W emulsion was reduced from 161.412±8.650 to 24.632±2.263, the zeta potential increased from (-52.10±2.19) mV to (-5.13±0.31) mV and the particle size increased from (628.87±11.85) nm to (2 030.67±84.72) nm. The turbidity of Bacillus subtilis-containing O/W emulsion was reduced from 160.249±9.546 to 10.102±0.141, the zeta potential increased from (-45.24±1.79) mV to (-1.23±0.40) mV and the particle size increased from (519.25±18.37) nm to (2 004.23±113.45) nm. Meanwhile, the turbidity of Bacillus subtilis-free W/O emulsion was reduced from 784.525±34.654 to 53.916±4.832, the zeta potential increased from (-58.12±2.14) mV to (-4.91±0.27) mV and the particle size increased from (1 441.50±66.71) nm to (2 616.06± 111.04) nm. The turbidity of Bacillus subtilis-containing W/O emulsion decreased from 776.247±5.348 to 29.453±1.128, the zeta potential increased from (-52.14±2.41) mV to (0.49±0.04) mV and the particle size increased from (1 327.17±25.23) nm to (2 579.37±68.71) nm. Results showed that the turbidity of Bacillus subtilis-containing emulsion was significantly reduced (P< 0.05), zeta potential significantly increased (P< 0.05) and particle size significantly decreased (P< 0.05) in comparison with that of Basillus subtilis-free emulsion. In conclusion, Bacillus subtilis could promote the demulsification of soy protein-phospholipid composite emulsion during enzymatic hydrolysis.