Conventional methods for detecting tumors, such as immunological methods and histopathological diagnostic techniques, often request high analytical costs, complex operation, long turnaround time, experienced personnel and high false‐positive rates. In addition, these assays are difficult to obtain an early diagnosis and prognosis quickly for malignant tumors. Compared with traditional technology, electrochemical technology has realized the study of interface charge transfer behavior at the atomic and molecular levels, which has become an important analytical and detection tool in contemporary analytical science. Electrochemical technique has the advantages of rapid detection, high sensitivity (single cell) and specificity in the detection of tumor cells, which has not only been successful in differentiating tumor cells from normal cells, but has also achieved targeted detection of localized tumor cells and circulating tumor cells. Electrochemical biosensors provide powerful tools for early diagnosis, staging and prognosis of tumors in clinical medicine. Therefore, this review mainly discusses the development and application of electrochemical biosensors in tumor cell detection in recent years.