Deep ocean water (DOW) has been shown to enhance the functional components of fungi, resulting in increased health benefits. Therefore, using DOW for culturing fungi can enhance the cordycepin and adenosine of Cordyceps militaris (CM) and its protective effects on the liver. In this study, the antiliver fibrosis effects and mechanisms of ultrapure water-cultured CM (UCM), DOW-cultured CM (DCM), synthetic water-cultured CM, DOW, cordycepin, and adenosine were compared in the liver fibrosis mice induced by intraperitoneal injections of thioacetamide (TAA). The results indicated that DCM exhibited superior performance in reducing liver collagen accumulation, mitigating liver injuries, inhibiting proinflammatory factors and fibrosis-related factor (TGF-β1, Smad2/3, α-SMA, COL1A1) expression compared with UCM. DOW, cordycepin, and adenosine also performed antiliver fibrosis effect. Therefore, because DCM is rich in DOW and functional components, it can achieve anti-liver fibrosis effects through multiple pathways. These ameliorative effects are considerably superior to those of UCM.