Apoptosis of gastric cancer cells induced by cisplatin was investigated using laser Raman spectroscopy. Gastric cancer cells (SGC7901) were treated with 10 μg·mL-1 cisplatin for 24, 48 and 72 hours, then were divided into two parts, one for fluorescence staining, the other for collection of Raman spectra by means of scanning. The acquired spectra were then preprocessed by background elimination, smoothing, normalization, baseline correction, and peak fitting. Fluorescence staining result showed that the nucleuses from untreated group were uniformly stained, while those from the group treated for 72 hours were densely stained and broken. The spectra results revealed that the intensity of peaks associated with nucleic acid and protein decreased after the cells were incubated with cisplatin for 24, 48 and 72 hours. The intensity of peaks at 783, 1 002 and 1 343 cm-1 respectively fell to 52, 64 and 76 percent of the original value after 72 h of treatment, which indicated that cisplatin could induce apoptosis of gastric cancer cells and reduce the amount of nucleic acid and protein in the cells. The above results suggest that Raman spectra can provide abundant information about the changes in materials in cells and serve as an effective method for real time measurement of apoptosis.