Abstract: Taking moso bamboo stalks as raw material and the dry matter yield of moso bamboo stalks extract as the optimization index, the response surface methodology was used to optimize the process parameters of pressurized hot water extraction of compounds from bamboo stalks. The optimum extraction conditions were as follows: 4-year-old moso bamboo, extraction temperature of 165 ℃, extraction time of 30 min, solid-liquid ratio of 1∶12.5. Under these conditions, the dry matter yield was 12.44%, which was close to the predicted value(12.56%). The chemical composition of the pressurized hot water extract and the heating reflux water extract of moso bamboo stem was detected by gas chromatography-mass spectrometry(GC/MS). The results of GC/MS analysis showed that the chemical composition(content of 53.30%) of 23 kinds of pressurized hot water extracts from bamboo stems was much higher than that of 13 kinds of heated reflux water extracts(27.90%), and mainly contained active ingredients such as coniferaldehyde, vanillin, syringaldehyde, acetosyringone, 4-vinyl-2-methoxyphenol, 2, 3-dihydrobenzofuran and furfural.