With the development of society, the incidence of colorectal cancer in China is increasing year by year, and it has become the second tumor in terms of incidence in areas with good economic development. Moreover, the incidence of colorectal cancer (especially non-hereditary colorectal cancer) increases gradually with age, and it can be said that it is very close to each of us. The top two most likely causes of colorectal cancer are recognized as environmental (especially dietary) factors and genetic factors. Environmental factors include social development, lifestyle changes and dietary structure, which will not be discussed in this article. This article focuses on the relationship between genetic factors and colorectal cancer. Hereditary colorectal cancer has a low age of onset and is prone to the combination of tumors of other organs with certain genetic characteristics, and it is estimated that at least 20% of colorectal cancers are genetically related. With the progress of research on the relationship between colorectal cancer and heredity and the improvement of diagnostic techniques, the understanding of part of the hereditary factors of familial colorectal cancer is gradually clear, and part of the disease can be prevented through close screening and regular medical examination and treatment for people at high risk of colorectal cancer. The two most common types of hereditary colorectal cancer, Lynch syndrome (LCS) and familial adenomatous polyposis (FAP), are both autosomal dominant disorders. Lynch syndrome is the most common form of hereditary colorectal cancer and is caused by germline mutations in the mismatch repair gene (MMR). Lynch syndrome also often leads to the development of tumors in other organs, and 40-60% of women with Lynch syndrome may develop endometrial cancer by age 70. Other associated tumors include ovarian cancer, stomach cancer, small intestine cancer, hepatobiliary cancer, pancreatic cancer, and brain tumors. Relatives of patients with Lynch syndrome have a 45% risk of colorectal cancer for men and 35% for women, and a 31-64% risk of endometrial cancer before the age of 70. Therefore, these high-risk groups should have regular colonoscopies and gynecologic visits. The time frame for colonoscopy for the general population is once every 5-10 years, while colonoscopy for patients with Lynch syndrome is recommended under the guidance of a specialist and vigilance is needed for the development of tumors in other areas. Familial adenomatous polyposis is characterized by a large number of adenomatous polyps in the colorectum, which can also occur throughout the gastrointestinal tract. A small number of polyps may be less than 100, while many thousands may cover the entire colorectum, and these polyps can grow to a point where they become malignant and turn into colorectal cancer. Not everyone with Lynch syndrome will develop colorectal cancer, while patients with familial adenomatous polyposis will develop colorectal cancer in close to 100% of their lifetime, and the onset of the disease is young, at 20-30 years of age. Familial adenomatous polyposis is often combined with germline mutations in the APC tumor suppressor gene and is not difficult to diagnose through family history and colonoscopy. Treatment of familial adenomatous polyposis is primarily surgical, with procedures such as total colorectal resection ileal pouch anal canal anastomosis and preservation of the rectum as options. Preventive colorectal resection is currently recommended because it is almost 100% carcinogenic. Professional doctors will consider the patient’s age, occupation, and environment; the density, location, and morphology of the adenoma, the age of onset in family members, the location of the APC gene mutation, and the effect of surgery on pregnancy and male function. The disease causes diarrhea, abdominal pain, blood in the stool symptoms and many other factors to consider the timing and procedure of preventive surgery. There are also some genetic factors of familial colorectal cancer that are not clear, and it is believed that with the advancement of technology will further clarify the genetic changes of these diseases and find better prevention and treatment solutions.