Synergistic antibacterial effect as a promising strategy against foodborne pathogens is compelling since the development of novel antibacterial agents is not so easy. Here we investigated the synergistic effect of cell wall hydrolase Lys14579 and cinnamaldehyde (CAL) against emetic Bacillus cereus. The MICs of Lys14579 and CAL against emetic B. cereus were 25 and 200 μg/mL, respectively. The combination of Lys14579 and CAL displayed a synergistic antimicrobial effect with a Fractional Inhibitory Concentration Index (FICI) of 0.375. Bactericidal assays revealed that this combination had better bactericidal performance than either substance alone. Furthermore, the combination of Lys14579 and CAL effectively inhibited the biofilm formation of emetic B. cereus at the concentrations of 6.25 and 50 μg/mL, respectively. Additionally, it down-regulated the cereulide synthetase gene (cesB) expression at the transcription level and reduced swarming motility by 55%. Scanning electron microscope and PI uptake assays further demonstrated that the combination accelerated the disruption of emetic B. cereus cells. Finally, the synergistic preservative effect of this combinational was observed in boiled rice and fresh lean beef. Thus, the combination of Lys14579 and CAL represents a potential synergistic strategy for controlling emetic B. cereus contamination in the food industry.