Abstract: So far，the study of the phase behavior of hydrocarbon fluids has been relatively mature. It could supply corresponding
theoretical guidance and technical support for the efficient development of the oil and gas reservoirs. However，the effect of
porous media on phase behavior mostly is ignored. Therefore，it is crucial to study the phase behavior of fluids in porous media
with due consideration of the interactions of the fluids and porous media. With the further development in this field，advantages
of the ultrasonic detection such as no limit of pressure and temperature，no effect on fluid compositions，low cost and no harm
to human beings have received increasingly attention and the technique is gradually being used in phase behavior of fluids in
porous media. In this paper，with reference to abundant literature at home and abroad，detection mechanism of the ultrasonic
wave is described briefly and research advances of the ultrasonic detection in phase behavior of gas hydrates and condensate
gas system is summarized emphatically. And，the existing problems and future research of this technique are also identified.

Key words: ultrasonic detection, porous media, natural gas hydrates, condensate gas, phase behavior