Although a 74-year-old man with gastric cancer with pyloric stenosis(cT4aN[+]M0, Stage Ⅲ)had undergone surgery, he was diagnosed with peritoneum dissemination. He received bypass surgery, and an intraperitoneal access port was implanted in his subcutaneous space. Postoperatively, he received 4 courses of SOX therapy. In treatment effect, the primary tumor showed no change, and ascites developed. Therefore, we changed the chemotherapy regimen in intravenous and intraperitoneal paclitaxel combined with S-1 therapy. After starting this regimen, the primary tumor decreased in size, and the pyloric stenosis improved. Currently, the patient is alive without recurrence for 5 years and 8 months after intravenous and intraperitoneal paclitaxel combined with S-1 therapy and receiving this treatment regularly.