Previous studies have demonstrated that human ether-à-go-go-related potassium channel (hERG1) is highly expressed in many tumor cell lines, as well as in primary human cancers, and, hence, have a critical role in cell cycle progress and proliferation. In this study, hERG1 expression was investigated in gastric cancer by immunohistochemistry and/or reverse transcription polymerase chain reaction (RT-PCR). It was discovered that hERG1, which was negatively expressed in surrounding non-tumor tissues, switched to aberrantly positive expression in gastric cancer. Statistically, there were significant differences in hERG1 protein expression according to factors such as serosal invasion, venous invasion, lymph node metastases, other organ metastases, and stage. The mean survival time for the hERG1-positive expression group was significantly shorter than the negative group, the survival rates for the positive group were significantly lower than the negative group, and hERG1 expression was found to be an independent prognostic factor. In summary, hERG1 channel was proved to be a potential biomarker for gastric cancer invasion and survival.