Most of the intestinal flora colonize at the distal end of the digestive tract sharing many enzymatic reactions with their hosts. It is an essential part of the human body and has a significant impact on health. Dietary fiber phytonutrients and micronutrients in the diet provide nutrition for intestinal flora regulate the diversity and richness of intestinal flora and play an important role in preventing and treating some diseases. Studies have shown that dietary fiber is highly fermented and expanded by the intestinal flora producing short-chain fatty acids mainly in the colon influencing host metabolism and the immune system indirectly shaping the intestinal flora and also participating in cell growth intestinal barrier and ion transport and increasing the expression of antibacterial and host defense genes. 90% ~ 95% of dietary phytonutrients are converted into highly bioavailable metabolites by intestinal flora which significantly changes microbial diversity and plays a positive role in preventing metabolic syndrome of the high-fat diet. Vitamins and micronutrients provide essential nutrients to the intestinal flora promote competition with pathogenic bacteria modulate the immune response and alter the intestinal flora and gastrointestinal function. The intestinal flora regulates the systemic status of various nutrients and is beneficial to the health of the organism.