Abstract: Objective To observe the effect of Klotho gene on the growth of gastric cancer cell line GC-7901. Methods Klotho vector was constructed. Gastric cancer GC-7901 cells were divided into Klotho group (GC-7901 cells were transfected with p Zs Green1-C1-Klotho vector), negative control group (GC-7901 cells were transfected with empty virus vector), blank control group (GC-7901 cells). The expression of Klotho protein was detected by Western blot. The cell proliferation was detected by CCK-8 assay. The cell apoptosis and cell cycle were determined by flow cytometry. Results The expression of Klotho protein in gastric cancer cell line GC-7901 was lower than that in normal gastric cell line GES-1 (0.19 ±0.01), P<0.05. The expression of Klotho protein in Klotho group (0.81 ±0.12) was significantly higher than that in the negative control group (0.24 ±0.06) and the blank control group (0.22 ±0.04), P<0.05. The gastric cancer cell proliferation rate of the Klotho group[(62.26 ±13.24)%] was significantly lower than that in the negative control group[(99.14 ±21.53)%] and the blank control group[(100.00 ±1.03)]%, P<0.05. The apoptosis rate of gastric cancer cells in the Klotho group[(23.31 ±2.54)%] was significantly higher than that in the negative control group[(4.76 ±0.15)%] and the blank control group[(4.67 ±0.13)%], P<0.05. The percentage of G0/G1 phase in gastric cancer cells in the Klotho group[(25.26 ±2.63)%] was significantly higher than that in the negative control group[(4.91 ±0.17)%] and the blank control group[(4.83 ±0.16)%], P<0.05. Conclusion Klotho protein in gastric cancer cells are low expression. The high expression of Klotho gene can reduce the proliferation of gastric cancer cells, promote the apoptosis of gastric cancer cells and inhibit the cell cycle.