Senescent cancer cells often evade immune clearance to exert profound effects on cancer progression and therapy resistance. Improving immunosurveillance to eliminate senescent cancer cells is a crucial measure to enhance anti-cancer therapy. Bazi Bushen (BZBS) is a traditional medicine with the function of relieving fatigue and delaying ageing, but its role in tumor treatment remains poorly understood. Herein, we find that BZBS promotes immunosurveillance of both chemotherapy- and oncogene-induced senescent liver cancer cells, further leading to enhanced chemotherapy efficacy and dramatic tumor repression in mice. Mechanistically, BZBS induces mitochondrial DNA leakage by mitochondrial damage to further activate cGAS-STING signaling in macrophages. Subsequently, cGAS-STING signaling activation in macrophages recruits CD8