Intestinal microecology (IM) is the largest and most important microecological system of the human body. Furthermore, it is the key factor for activating and maintaining the physiological functions of the intestine. Numerous studies have investigated the effects of the gut microbiota on the different tissues and organs of the human body as well as their association with various diseases, and the findings are gradually being translated into clinical practice. The gut microbiota affects the occurrence, progression, treatment response, and toxic side effects of tumors. The deepening of research related to IM and tumors has opened a new chapter in IM research driven by methods and technologies such as second-generation sequencing and bioinformatics. The IM maintains the function of the host immune system and plays a pivotal role in tumor-control drug therapy. Increasing evidence has proven that the efficacy of tumor-control drugs largely depends on the IM balance, and strategies based on the IM technology show promising application prospects in the diagnosis and treatment of tumor. The Tumor and Microecology Professional Committee of the Chinese Anti-cancer Association gathered relevant experts to discuss and propose the "Chinese guidelines for integrated diagnosis and treatment of IM technologies in tumor application (2024 Edition)," which was established based on the research progress of the application of the IM technology in tumor to provide a basis for the standardization of the diagnosis and treatment of the IM technology in the tumor.