The objective of this study was to optimize some parameters of fresh chili preservation technology by controlled atmosphere (CA) with 3 factors of corresponding surveyed domains: temperature (8 - 12oC), concentration of oxygen (2-4 percent) and concentration of carbon dioxide (3-6 percent). Experimental plan includes 9 experiments following 23 plan repeating at center with the objective function as indicators of chili quality including total sugar content (percent), organic acid content (percent) and sensory quality (score). Nine experiments were concurrently conducted on a multifunction CA system in which parameters can be controlled and automatically monitored with good accuracy: temperature +/- 0.5oC, humidity +/- 2 percent, oxygen concentration : +/- 0.5 percent, carbon dioxide concentration +/- 0.5 percent. The result was the successful determination of optimal experiment factors including temperature of 10.8oC, oxygen concentration of 8 percent, and carbon dioxide concentration of 6.0 percent. The corresponding objective functions were achieved after 35 storage days with 3.65 percent of total sugar content, 4.06 percent of total organic acids, and good sensory quality (17.29/20 scores).