Metastasis of colon cancer is usually detected through imaging examination and physical abnormalities. After initial examination, puncture biopsy of local tumor and pathological examination can be conducted to confirm the diagnosis; those who are examined only when the corresponding symptoms appear often miss the early stage of the disease when the diagnosis is confirmed. For the examination of metastasis of colon cancer, the commonly used clinical methods include ultrasound, CT, MRI, PET-CT, puncture biopsy and pathological staining and sectioning. The common metastatic sites of colon cancer are liver, lung, etc., and specific appropriate or targeted examinations can be chosen according to different sites. Combined with medical history, if occupying lesions are found, the diagnosis can be basically determined without pathological examination; puncture biopsy of occupying mass can clarify whether it is colon cancer metastasis. After diagnosis of colon cancer, active treatment, regular review, observation, early detection of metastasis, and timely medical treatment for uncomfortable symptoms are needed.