Abstract: Objective To explore the relationship of C-reactive protein （CRP） with peritoneal cavity metastasis and prognosis of gastric carcinoma. Methods In a retrospective study， the clinic data of 150 patients with advanced gastric carcinoma treated with first-line chemotherapy， including 112 patients with peritoneal cavity metastasis and 38 patients with nonperitoneal cavity metastasis， was analyzed. Influences of CRP， serum albumin， Eastern Cooperative Oncology Group performance status （ECOG PS） and peritoneal cavity metastasis on the prognosis were studied by univariate analysis and Cox proportional hazard mode. The difference of CRP， serum albumin and ECOG was analyzed between patients with or without peritoneal cavity metastasis. Results The results of univariate analysis showed that the factors associated with poor prognosis were CRP， serum albumin， ECOG and peritoneal cavity metastasis. According to multivariate analysis， peritoneal cavity metastasis was the only factor independently associated with prognosis. Compared with nonperitoneal cavity metastasis group， CRP （P=0.006） and ECOG PS （P＜0.001） were significantly increased， while serum albumin group（P＜0.001） was significantly decreased in peritoneal cavity metastasis group（P＜0.001）. Conclusion Compared with non-peritoneal cavity metastasis group， response of systemic inflammation was significantly upregulated in peritoneal cavity metastasis group with poorer prognosis， which could provide a treatment strategy for advanced gastric carcinoma patients with peritoneal cavity metastasis from standpoint of inflammation.