The preventive effects of aqueous Qingzhuan tea (QBT) extract on metabolic dysfunction-associated fatty liver disease (MAFLD) and ulcerative colitis (UC) were examined. Twenty eight-week-old female C57BL/6 mice were randomly divided into negative control (NC), model control (MC), low-dose (LD), and high-dose (HD) groups. The MAFLD and UC models were established by high-fat feeding combined with 2.5% dextran sulfate sodium in drinking water ad libitum. The body weight, liver weight, colon length, biochemical markers, and blood lipid parameters of the liver, and the histopathological characteristics and inflammatory factor expression of the colon and liver were determined. Compared with that of the NC group, the MC group exhibited a significantly increased liver index of 0.06. The livers of the MC group were yellow and greasy. Under the microscope, numerous lipid vacuoles were observed. In addition, the colon was remarkably shortened to 4.38 cm, with a disordered structure, severely damaged glands, and significant inflammatory cell infiltration. Compared with that of the MC group, the LD and HD groups had significantly lower liver indexes. The livers of these treatment groups exhibited a similar color to that of the NC group and were not greasy. Microscopy images showed significantly fewer lipid vacuoles. Moreover, the colons were significantly lengthened up to 5.04 and 5.28 cm, respectively. The glandular structure was restored, and inflammatory cell infiltration decreased considerably. In the LD group, the alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein cholesterol, total cholesterol, and triglyceride contents were 67.58, 44.36, 4.57, 7.61, and 1.46 mmol/L, respectively. In the HD group, they were 53.83, 28.05, 3.44, 5.87, and 0.68 mmol/L, respectively, indicating a significant reduction. Compared with those of the MC group, the transcription levels of pro-inflammatory factors and the expression levels of proteins related to inflammatory pathways in the LD and HD mice were significantly lower (P<0.05). These findings revealed that the aqueous QBT extract can effectively prevent MAFLD and UC. The underlying mechanisms may be associated with the inhibition of inflammatory signaling pathways.