Abstract Background and aim: The mRNA expression-based stemness index (mRNAsi) is an index for describing stemness features of cancer. The progression of cancer means acquisition of stemness features and progressive loss of differentiated characteristics. The aim was to find a mRNAsi-related gene in gastric cancer (GC) and explored its functions. Methods: Bioinformatics analysis were assessed by The Cancer Genome Atlas (TCGA) database and microarray GSE66229 dataset. TCEALE expression in tissues and cell lines was assessed by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. Experiments of gain-of-function were employed to find the impacts of TCEAL7 on cell proliferation，migration and invasion abilities，and stemness properties of GC. Results: The expression of TCEAL7 was downregulated in GC. However，high expression of TCEAL7 was parallel with a worse prognosis. Overexpressed TCEAL7 could inhibit gastric cancer cell proliferation，migration and invasion abilities，which also attenuated spheroid formation and decreased numbers of stem-like CD44high/CD24high cells. The nomogram which included clinical features and TCEAL7 expression showed good accuracy and discrimination for predicting the prognosis of patients with GC. Conclusions: TCEAL7 was identified as mRNAsi-related prognostic factor in GC，which inhibited cellular malignancy，and impaired stemness properties.