The main ingredient of the study is the leaves of the lingonberry. The liquid-liquid extraction technique was employed to analyze the primary constituents of Vietnamese kumquat leaves and to formulate pH-sensitive liposomes containing Vietnamese kumquat leaf flavonoids. The study also investigated their in vitro release at various pH levels and their inhibitory effect on HepG2 cells. Eighteen fractions were obtained using ultrasound-assisted extraction and macroporous resin purification. The optimal components were analyzed using the activity tracking method for liquid-liquid analysis. pH-sensitive liposomes were prepared using the ethanol injection method, which was combined with carboxymethyl chitosan surface modification. The liposomes were characterized using Fourier transform infrared spectroscopy, particle size analysis, polydispersity index measurement, zeta potential determination, and the dialysis method to analyze their in vitro release capability. The inhibitory effect of the liposomes on HepG2 cells was determined through analysis of cell proliferation, migration, and the cell cycle. The results showed that the macroporous resin effectively increased the purity and antioxidant capacity of the flavonoids. The concentration of purified flavonoids reached 899.44 mg/g. HPLC-MS analysis identified nine components, including epicatechin-3-O-cinnamate, catechin, dihydromyricetin, glycyrrhizic chalcone A, quercetin-3β-D-glucoside, kaempferol-3-O-L-rhamnoside, isorhamnetin-3-6-gallic acid glucoside, kaempferol 3-(6-gallic acid lactose), and quercetin 3-(2-gallic acid ellagic acid glucoside). The encapsulation efficiency of the liposomes prepared with this flavonoid is 81.77±3.02%, with a particle size of 408.30±2.23 nm and a uniform particle size distribution. When the concentration of carboxymethyl chitosan is 0.4%, the solution exhibits the highest stability, as indicated by the highest absolute value of x-potential. In vitro release experiments have shown its pH sensitivity, with a cumulative release of 98.03±3.18% in 48 hours at a release medium pH of 4.0. Additionally, it conforms to the Weibull model. Cell experiments further demonstrate that compared to liposomes without carboxymethyl chitosan encapsulation, liposomes with carboxymethyl chitosan encapsulation exhibit pH sensitivity, enhance the inhibitory ability of HepG2 cells, and block the HepG2 cells from staying in the S and G2 phases.