Objective: To investigate and evaluate the mastery and recognition degree of Chinese clinicians on the 2015 edition of the Chinese Criteria for Diagnosis and Treatment of Colorectal Cancer in order to provide useful suggestions for updating and formulating diagnosis and treatment standards. Methods: Simple random sampling was used to conduct a questionnaire survey in 1500 colorectal cancer-related doctors in general hospitals and cancer hospitals from 115 cities in China. The study included the following guidelines: (1) Chinese Criteria for Diagnosis and Treatment of Colorectal Cancer (2015 edition); (2) Chinese Society of Clinical Oncology Colorectal Cancer Guidelines 2017 (CSCO 2017); (3) National Comprehensive Cancer Network (NCCN) Colon Cancer Guidelines 2017.v1; (4) European Society for Medical Oncology (ESMO) Rectal Cancer Guidelines. The survey was carried out in 2017 and 2019 respectively. In the first phase, the questionnaire included 4 dimensions (guideline cognition, detection and diagnosis, pathology and staging, treatment), and 1500 questionnaires were distributed. In the second phase, the questionnaire contained 3 dimensions (basic information, current treatment status of metastatic colorectal cancer, academic expectations), and 350 questionnaires were distributed. Case (%) was used to indicate the categorical variable data, and chi-square test was used for comparison between groups. P <0.05 indicated that the difference was statistically significant. Results: In the first phase, 1472 valid questionnaires were collected, and the questionnaire efficiency was 98.1% (1472/1500). In the second phase, 337 valid questionnaires were collected, and the questionnaire efficiency was 96.3% (337/350). In the survey of the first phase, doctors had some knowledge and compliance with various guidelines, but the most familiar one was the NCCN guidelines, accounting for 90.7% (1335/1472). In the dimension of detection and diagnosis, the overall correct rate was 64.1% (944/1472). The correct rate of doctors in the first-tier cities was 55.6% (148/266), which was lower than 59.1% (182/308) and 72.9% (369/506) in the second- and the third-tier cities, and the difference was statistically significant (χ(2)=42.140, P <0.001). More than 60.0% (883/1472) of doctors was clear about the specification requirements of the staging evaluation and pathological examination. However, in terms of rectal cancer local staging evaluation, the ratio of doctors who would choose rectal MRI in the first-tier cities was lower than that of those in other tier cities [51.5% (137/266) vs. 65.6% (202/308), 63.2% (320/506) and 61.2% (240/392)], and the difference was statistically significant (χ(2)=41.886, P <0.001). In the dimensions of staging evaluation and pathological examination, there were no statistically significant differences in cognition between general and specialist hospitals ( P >0.05). In the treatment dimension, 79.8% (1175/1472) of doctors considered the preoperative treatment as a necessary option for patients with middle and low locally advanced (over cT3) rectal cancer. 46.3% (681/1472) of doctors, including 60.3% (433/718) of surgeons, and 31.4% (225/716) of physicians, had a vague idea that irinotecan could not be used for postoperative adjuvant treatment of colorectal cancer. In the survey of the second phase, 93.8% (316/337) of doctors approved potentially curative systemic (conversion) therapy, and 95.3% (321/337) of doctors followed the clinical guidelines in the treatment of metastatic colorectal cancer. Regarding academic expectations, the clinician's concern for surgery was more practical, and 79.2% (267/337) of doctors wanted to know the best options of conversion therapy for potentially curable metastatic colorectal cancer. In contrast, the clinician's concern for internal medicine was more exploratory, and 80.1% (270/337) of doctors focused on selecting targeted drugs and the sequence of treatment. Conclusions: This investigation has a preliminary understanding of the diagnosis and treatment of colorectal cancer in China. (1) There are many guidelines for doctors' reference, but doctors' understanding of domestic guidelines is not as good as NCCN guidelines. (2) The degree of understanding of the guidelines varies significantly among doctors in different cities. (3) The promotion of guidelines should focus on basic concepts and theories. (4) The detection, diagnosis, and treatment of colorectal cancer should be better trained and promoted. (5) The concept of conversion therapy for metastatic colorectal cancer is highly recognized.