This study investigated the protective effect of Vitamin U on liver injury induced by aflatoxin B1 (AFB1) in maternal mice. 25 pregnant ICR mice were randomly divided into five groups: the AFB1 group (AF, 0.3 mg AFB1/kg b.w.), the Vitamin U group (U, 50 mg Vitamin U/kg b.w.), the AFB1 + Vitamin U group (AU, 50 mg Vitamin U /kg b.w. + 0.3 mg AFB1/kg b.w.), the control group (DMSO), and the MOCK group (distilled water). They were administered substances by gavage every day for 28 days. Results indicated that exposure to AFB1 increased the liver index and caused histological disruptions. Elevated serum levels of ALT and ALP were observed, along with a significant increase in liver MDA content and a decrease in GSH-Px and T-SOD levels. Moreover, the Keap1 and Hmox1 gene was downregulated with statistical significance, while the IL1β and TNFα gene were significantly upregulated. Vitamin U was demonstrated by the organized structure of liver cells in tissue slices, effectively reducing liver cell necrosis. This intervention was associated with a significant decrease in serum ALT and ALP activities, as well as a significant decrease in liver MDA content. Additionally, there were significant increases in liver T-SOD and GSH-Px levels, along with upregulation of mRNA and protein expression of Nfr2, Hmox1 and Keap1, and downregulation of mRNA expression of the IL1β gene. In summary, Vitamin U mitigated oxidative stress-induced liver injury by modulating the Nrf2/Hmox1 signaling pathway and inflammatory factors affected by AFB1.