Colorectal cancer is one of the most common gastrointestinal tumors, and its incidence has been on the rise recently, increasing at an average rate of about 4% per year, posing a serious threat to human health. The current treatment method is mainly surgery, supplemented by radiotherapy and chemotherapy. The emergence of some new molecularly targeted drugs, which are more effective and have fewer side effects than traditional drugs, is receiving more and more attention from clinicians. K-ras gene is the most direct and effective way for doctors to understand the oncogene status of colorectal cancer patients. It can screen out patients with colorectal cancer who are effectively treated with anti-EGFR (epidermal growth factor receptor) targeted drugs, and realize individualized treatment for tumor patients, thus achieving good prognosis and prolonging patients’ survival. In addition, even for patients who have just resected the primary lesion of colorectal cancer, as most patients will have recurrence and metastasis within 5 years, the more advanced the disease stage, the higher the risk of recurrence and metastasis, early detection of K-ras can also understand the patient’s risk of recurrence and metastasis, so as to prepare for the best treatment in the future. The latest research results of K-ras gene testing in China show that about 2/3 are wild type. At this time, if K-ras gene test is done, adding targeted drugs, such as Epiduo, on top of chemotherapy can increase the efficiency by about 20%. Therefore, patients with colorectal cancer should undergo K-ras gene testing as early as possible after diagnosis, so that about 60% of patients with K-ras wild type can hopefully seize the best treatment period and obtain good treatment results.