Abstract: This paper studies the Raman spectra of the fluid inclusions under uniform state with natural fluid inclusions as the research object, combining the two testing methods of laser Raman spectra and the heating-and-freezing stage. It has important references for finding the ancient fluid properties under high temperature and pressure, knowing the phase equilibrium of the earth interior material, the mineral dissolution, precipitation, and migration, and the function of deep rock melting. The high temperature characteristics of H₂O-CO₂, H₂O-CH₄ and H₂O-CO₂-CH₄ mixed fluids were analyzed in situ by using laser Raman spectroscopic probe combined with a micro-thermal platform. The influence of the non-polar molecules (CO₂, CH₄) on the hydrogen bond water molecules at high temperature uniform state was mainly discussed.