In order to explore the changes of intestinal flora and serum levels of relevant substances in patients with gastric cancer before and after surgery with carbon nanoparticle laparoscopy, a total of 180 patients with early distal gastric cancer who adopted laparoscopic radical gastrectomy for distal gastric cancer in the general surgery department of TCM Hospital of Shi Jia Zhuang City from January 2018 to January 2020 were selected and randomly divided into two groups: traditional laparoscopic operation (control group) and carbon nanoparticle laparoscopic operation (experimental group) were adopted for treatment for the two groups, respectively. Postoperative evaluation included the difference between the two groups in the operative time, the efficiency of intraoperative lymph node dissection, and the number of lymph node detection. The adverse reactions, changes of intestinal flora before and after surgery in the two groups, and the serum levels of epidermal growth factor receptor (EGFR), interleukin-32 (IL-32), and gastrin 17 were evaluated. In the experimental group, the success rate of carbon nanoparticle tracer black staining reached 100%, and the operation time of the experimental group was significantly shorter than that of the control group (P < 0.05). The lymph node detection rate of the experimental group was higher than that of the control group (P < 0.05), but there was no significant difference in the lymph node metastasis rate between the two groups (P > 0.05). The sentinel lymph node sensitivity of the experimental group reached 92.3%, and the specificity, accuracy, and positive and negative prediction rates reached 100%; the experimental group patients were with an obviously higher incidence of level I-II gastrointestinal reaction (P < 0.05). Postoperative increases in Bifidobacteria and Lactobacillus were observed in both groups, while decreases in Enterococcus and Escherichia coli were observed in both groups (P < 0.05). Moreover, the degree of increase and decrease in the experimental group was greater than that in the control group (P < 0.05). The serum levels of EGFR, IL-32, and gastrin 17 in the two groups were significantly lower than those in the control group on 3 d, 7 d, and 15 d after surgery (P < 0.05). In the radical gastrectomy for distal gastric cancer, carbon nanoparticle laparoscopy was not only helpful for the localization of small tumors but also for the thorough dissection of lymph nodes after the surgery, and the postoperative adverse reactions of carbon nanoparticle laparoscopy were also less, which was of great significance for the improvement of intestinal flora and the reduction of serum levels of EGFR, IL-32, and gastrin 17 in gastric cancer patients.Copyright © 2021 Liping Bai et al.