Ebullition is one of the main pathways for the release of CH₄ from natural water bodies. It is important to accurately quantify the amount of ebullition in water bodies in order to distinguish between their ‘sink’ and ‘source’ characteristics. However, the discontinuity and uncertainty of ebullition in natural waters make it difficult to monitor the process. To meet the challenge of ebullition monitoring, a method for continuous monitoring of the ebullition process has been proposed by improving the inverted funnel bubble flux monitor. The measurement object of this method is the volume of bubbles released in the monitored water area during a fixed period of time. The theoretical range of this method is 3.6-132 mL/(m²·min) through indoor and outdoor experiments, and the measurement results can better characterize the variation characteristics of ebullitive flux in the slow-flowing water body with the depth of 10-40 m. This method was applied to continuously monitor methane ebullitive flux in Xiangxi Bay, Three Gorges Reservoir, and the influences of various environmental factors on methane ebullitive flux were analyzed. The results showed that during the measurement period, the variation range of methane ebullitive flux was 0.02-8.13 mg/(m²·d), and the ebullitive flux between sampling points showed high spatial-temporal variability. The ebullitive flux was positively correlated with water temperature and pH, and negatively correlated with water depth and conductivity; moreover, water depth might be an important factor in determining whether CH₄ was released by ebullition: after the water depth exceeded 38.35 m, the ebullitive flux was below 0.38 mg/(m²·d). However, whether the threshold value (38.35 m) was applicable to other tributaries of the Three Gorges reservoir requires further experimental verification. This study is useful to reveal the emission process of CH₄ bubbles in typical tributaries of the Three Gorges Reservoir.