Purpose About 15%-40% of gastric cancer patients have peritoneal metastasis, which leads to poor prognosis. Hyperthermic intraperitoneal chemotherapy (HIPEC) is considered to be an effective treatment for these patients. This study evaluated the efficacy and safety of HIPEC in patients with gastric cancer diagnosed from laboratory tests. Methods The clinical and pathological data of 63 patients with gastric cancer who underwent HIPEC in 2017-2021 were prospectively recorded. Fifty-five patients underwent cytoreductive surgery + HIPEC, and eight patients received HIPEC alone. The factors associated with HIPEC safety and efficacy were analyzed. The primary endpoint was overall survival. Results The average patient age was 54.84 years and 68.3% of patients were male. Moreover, 79.4% of patients had a peritoneal carcinoma index (PCI) score of <= 7 and 61.9% had a completeness of cytoreduction score of 0. Because of peritoneal metastasis, 29 patients (46.03%) were classified as stage IV. Laboratory tests showed no differences in pre-HIPEC blood test results compared to post-HIPEC results after removing the effects of surgery. HIPEC treatment did not cause obvious liver or kidney damage. Serum calcium levels decreased significantly after HIPEC (P = 0.0018). The Karnofsky performance status (KPS) score correlated with the patient's physical function and improved after HIPEC (P = 0.0045). In coagulation tests, FDP (P < 0.0001) and D-dimer (P < 0.0001) levels increased significantly and CA242 (P = 0.0159), CA724 (P < 0.0001), and CEA (P < 0.0014) levels decreased significantly after HIPEC. Completeness of cytoreduction score was an independent prognostic factor. HIPEC did not show a survival benefit in patients with gastric cancer (P = 0.5505). Conclusion HIPEC is a safe treatment for patients with gastric cancer with peritoneal metastasis based on the laboratory tests. However, the efficacy of this treatment on gastric-derived peritoneal metastases requires further confirmation.