Cancer is a major public health problem worldwide，and effective early intervention and effica⁃ cy surveillance can reduce the risk of oncology and death in patients. In most cancers，circulating cell ⁃free DNA （cfDNA）concentration and its integrity may be an effective indicator for early diagnosis，progressive patient identi⁃ fication，and prognostic monitoring. The purpose of this paper is to review the efficacy of cfDNA concentration and its integrity in the diagnosis and treatment of different cancers，and to compare it with the current tumor markers commonly used in clinical practice to explore the value and prospect of this index in clinical practice.