Abstract: In order to investigate the influence of filter ventilation on the sour taste note of cigarette smoke, the release of acidic components in particulate matters and pH of mainstream smoke of cigarettes with different filter ventilation rates were determined, and the variations of sour taste of mainstream smoke of ventilated cigarettes were studied on the basis of taste active value. The results showed that:1) With the increase of ventilation rate of cigarette filter, the total release of acidic components and sour taste index of mainstream smoke decreased significantly, and the pH of mainstream smoke raised significantly. The sour taste index of particulate matters in mainstream cigarette smoke decreased by 0.13-0.39 and its pH raised by 0.11-0.13 when filter ventilation rate increased by 10%. 2) The sour taste index of mainstream cigarette smoke linearly negatively correlated to its pH with determination coefficient R² higher than 0.9. 3) The total release of acidic components, sour taste index and pH of mainstream cigarette smoke could be used as a key index to assess the influence of filter ventilation on the acid-base balance of mainstream smoke. The determination method of mainstream smoke pH adopted by this study is simple, efficient and suitable for analyzing the influence of filter ventilation on the sour taste of cigarette smoke.