Six yeast strains of the commercial brewing yeasts CICC1391 and CICC1471, the commercial baker yeasts CICC1339 and CICC1447, and the commercial alcohol yeasts CICC1286 and CICC1291 have been cultured under 1.0 MPa of pressure with N-2 and CO2 as pressure media. The concentration of intracellular trehalose and the activity of trehalose synthases complex have been measured. Also, the morphology changes of yeast cells have been observed by scanning electronic microscope. There was a positive correlation between the activity of trehalose synthase complex and the concentration of intracellular trehalose; and there was a negative correlation between the activity of trehalose synthase complex and the viability of yeast strains. Having been cultured for 3 h at high pressure of 1.0 MPa, the concentration of intracellular trehalose and the activity of trehalose synthases complex were improved by 50.1% to 116.4% and 45.2% to 219.1%, respectively, compared to those of atmospheric pressure culture. Under high pressure, many wrinkles appeared on the membrane surface of yeast cells. It has been found that yeasts are more sensitive to high pressure for having more and sharper wrinkles on their cell membranes.