Objective: This study aimed to optimize the pectin extraction yield from immature fruits of Guanxi pomelo by L. plantarum fermentation and analysis of the properties of pectin extracted by L.s plantarum fermentation. Methods: Taking the extraction yield of pectin as the index, orthogonal test was used to optimize the process conditions of fermentation of immature fruits of Guanxi pomelo by L. plantarum, and the content of galacturonic acid, degree of esterification, protein, water-holding capacity, oil-holding capacity, emulsifying activity and emulsion stability of pectin were determined. Results: The optimal conditions for fermentation of immature fruits of Guanxi pomelo by L. plantarum were as follows: fermentation temperature of 37 ℃, L. plantarum fermentation inoculum of 14%, liquid-solid ratio of 25∶1 (mL/g), and fermentation time of 12 h. Under the control of these conditions, the extraction yield of pectin was 11.60%, and the content of galacturonic acid; the degree of esterification, protein, water-holding capacity, oil-holding capacity, emulsifying activity and emulsion stabilities were about 26.13%, 68.58%, 0.53 g/g, 7.01 g/g, 14.33% and 33%, respectively. Conclusion: The extraction yield of pectin extracted by fermentation of L. plantarum was similar to that of the acid process, and the obtained pectin was highly esterified pectin with good application properties.