Colorectal cancer is the third most common malignant tumor and the fourth major cause of cancer-related death in the world, which poses a serious threat to human health. The occurrence and development of colorectal cancer is a multi-step and multi-factor process, which involves the activation, mutation, inactivation and deletion of many tumor regulatory factors through a variety of signal pathways. Studies have shown that about 80% of colorectal cancer evolves from colorectal adenomas, and this process takes an average of about 10 years. Therefore, studying the factors affecting the occurrence and development of colorectal adenoma can reduce or avoid the risk factors, and meanwhile allow full play to the advantages of the protective factors, and then affect the occurrence of colorectal adenoma and ultimately reduce the occurrence of colorectal cancer. Based on the research progress at home and abroad, the authors address the risk factors and protective factors for the pathogenesis of colorectal adenoma from many aspects.