Description: The aim of the study was to explore the feasibility of diffusion-weighted magnetic resonance imaging (DW-MRI) in the depiction of gastric cancer and to investigate the signal characteristics and apparent diffusion coefficient (ADC) of gastric cancer. An institutional review board-approved protocol was developed for this prospective study. DW-MRI was performed on 101 patients with gastric cancer that was detected by gastroscopy biopsy. The optimal number of excitations (NEX) for DW-MRI was determined, and the signal characteristics of gastric cancer on DW-MRI were analyzed. The ADC of gastric cancer was measured by two experienced radiologists independently, and the reproducibility of measurement was investigated by the Bland–Altman analysis. When DW-MRI was used with four NEXs, areas of gastric cancer showed a good contrast and contrast-to-noise ratio. Four kinds of signal characteristics of gastric cancer were observed on DW-MRI: uniformly high signal, inner high signal, and outer low signal (two-layer type), high–low–high signal (three-layer sandwich type), and mixed type. The mean ADC of gastric cancer measured by two observers was (1.18 ± 0.29) × 10 −3 mm 2 /s and (1.20 ± 0.31) × 10 −3 mm 2 /s respectively, which showed good agreement with Bland–Altman analysis (95% limits of agreement: −0.16 to +0.19 × 10 −3 mm 2 /s). Gastric cancers have various signal characteristics on DW-MRI and the reproducibility of ADC measurement is satisfactory. DW-MRI is helpful in the depiction of gastric cancer.