The invention relates to an acellular DNA-based cancer inchoate diagnosis kit and application thereof, belonging to the field of medicine bioinstrumentation. The acellular DNA-based cancer inchoate diagnosis kit comprises a compound or composition capable of enhancing human immunity, and a related reagent for quantitatively detecting acellular DNA in human body fluid. The compound or composition capable of enhancing human immunity includes but not limited to dendritic cell vaccine, an immune checkpoint inhibitor, a compound capable of improving the CD<4+> and CD<8+>T cell proportion in a human body, and traditional Chinese medicines with immunity activation or immunity enhancement efficacy.