We developed an accurate method to calibrate Raman system for measuring the concentrations of dissolved gases in aqueous geo-fluids at high pressure, and determined CO2 solubility in water at temperatures from 273.15 to 573.15 K and pressures from 10 to 120 MPa. The Raman peak area ratio (PAR) and peak intensity ratio (peak height ratio, HR) of the upper band (at similar to 1390 cm(-1)) of CO2 Fermi dyad to the OH stretching band of water in homogeneous CO2 solutions were obtained over wide temperature, pressure, and concentration ranges. Pressure and concentration (mCO(2)) show little effects on PAR/mCO(2) and HR/mCO(2), while PAR/mCO(2) increases linearly with temperature from 273.15 to 573.15 K, and HR/mCO(2) decreases linearly with temperature at a different rate at temperatures below and above 404.45 K. The solubility data obtained from 298 to 523.15 K are consistent with previous experimental and thermodynamic studies. However, predictions from commonly-used thermodynamic models for temperatures below 298.15 K and above 523.15 K substantially deviate from the new measurements, suggesting that new or refined parameters are needed to improve these models. (C) 2014 Elsevier B.V. All rights reserved.