Objective This study was aimed to investigate the effects of ω-3 polyunstaurated fatty acids (ω-3 PUFAs) on the growth of gastric cancer cells in nude mice,and to find whether the Ros homolog gene Rho-associated coiled-coil containing protein kinase 1 (RHO-ROCK1) signaling pathway is involved.Methods 16 BALB/C nude mice were injected subcutaneously with SGC7901 gastric cancer cells to establish the tumor-bearing mouse model.The mice were randomized:control group (normal saline) and intervention group (ω-3 PUFAs).The mRNA expression of Ros homolog gene family,member A (RHOA),RHOC,and ROCK1 in tumor tissue were detected by quantitative polymerase chain reaction (qPCR).Immunofluorescence and Western blot were used to detect RHOA,RHOC,and ROCK1 protein expression.Results The volume and weight of the tumors in the ω-3 PUFAs group were slightly smaller than that in the control group (P ＞ 0.05).Compared to the control group,hematoxylin and eosin staining showed multifocal tumor necrosis in the ω-3 PUFAs group,while the tumors of the control group showed abundant blood supply.qPCR and Western blot showed that the mRNA and proteins expression of RHOA and ROCK1 in the ω-3 PUFAs group was significantly lower than those in the control group (P ＜ 0.05).The immunofluorescence redults also showed that the expression of these proteins in the ω-3 PUFAs group was slightly lower than that in the control group.Conclusions These results suggested that ω-3 PUFAs may affect the growth of gastric cancer in nude mice by affecting the expression of RHOA,RHOC and ROCK1,thus inhibiting the excessive proliferation of gastric cancer cells and leading to tumor necrosis.