The rhizome of Curcuma aeruginosa RoxB. was contain flavonoid compounds which potential as antibacterial activities. The objective was to determine factor extraction using maceration method by two level (low and high) half factorial design and followed independent factor: pH (2-6), temperature (30-80°C), ethanol concentration (20-80%), time (30-300 min), and liquid to solid ratio (10-100 mL/g). Total flavonoid content of extract was determined by colorimetric method with aluminum chloride, while antibacterial activity was screened using the disc-diffusion method against Escherichia coli and Staphylococcus aureus. Half factorial design was employed to determine the significant contribution of the factors extraction towards flavonoid content and antibacterial activities. The ethanol concentration (p<0.01) and liquid to solid ratio (p<0.05) are very significant contribution in extraction of rhizome C. aeruginosa to obtaining higher flavonoid contents (33.36 ± 29.81 mg QE/g extract). The highest of the zones of inhibition in C. aeruginosa extract against E. coli is 1.82 ± 2.40 mm that time extraction was very significant contribution (p<0.01), while antibacterial activity in S. aureus is significant contribution extraction by temperature and liquid to solid ratio (p<0.05) with highest value 8.75 ± 8.59 mm. Thus, the rhizome extract of C. aeruginosa can be proposed to be used as natural antibacterial.