Low-dose　decitabine　is　a　safe　drug　which　can　inhibit　DNMT　activity　to　promote　tumor　cell　apoptosis　without　inducing　cell　death.　This　study　investigated　the　clinical　efficacy　of　low-dose　decitabine　combined　with　chemotherapy　on　the　treatment　of　recurrent　and　refractory　gastric　cancer.　A　total　of　227　patients　with　refractory　gastric　cancer　were　retrospective　analyzed,　including　127　patients　treated　by　low-dose　decitabine　combined　with　chemotherapy　drugs　(observation　group)　and　100　cases　treated　by　chemotherapy　alone　(control　group).　CD4(+),　CD8(+),　and　CD4(+)/CD8(+)　proportion　in　peripheral　blood　lymphocytes　were　measured　by　ELISA.　Adverse　reactions　were　evaluated　by　the　common　toxicity　classification　criteria　according　to　WHO.　The　disease　control　rate　(83%)　and　median　survival　time　(10　months)　in　observation　group　were　significantly　higher　than　those　in　control　group　(P　＜　0.05).　CD3(+)　showed　no　obvious　changes　between　before　and　after　treatment　(P　＞　0.05).　However,　CD4(+)　and　CD4(+)/CD8(+)　proportion　in　both　groups　were　significantly　increased　after　treatment　(P　＜　0.05).　Compared　with　control,　CD4(+)　and　CD4(+)/CD8(+)　proportion　were　significantly　increased　in　observation　group　after　treatment　(P　＜　0.05).　The　incidence　of　adverse　reactions　in　observation　group　was　markedly　lower　than　that　in　control　group　(P　＜　0.05).　The　partial　remission　rates　were　47.2%　and　43.0%,　whereas　the　disease　control　rates　were　87.4%　and　81.0%　in　observation　group　and　control　group,　respectively.　The　application　of　low-dose　decitabine　combined　with　chemotherapy　can　improve　the　clinical　efficacy,　enhance　immune　function,　while　reduce　the　incidence　of　adverse　reactions　in　patients　with　refractory　gastric　cancer.