Abstract: The geological and biogeochemical cycle of methane and carbon dioxide in the ocean has an important impact on the marine environment and global climate change. In many deep-sea environments, methane and carbon dioxide usually diffuse in the form of bubbles or fluids, Methane is also one of the important indicators to detect the resources of natural gas hydrates. At present, in order to promote the study of marine carbon cycle and flux, research groups at home and abroad have proposed new technologies and methods for in-situ detection of dissolved methane and carbon dioxide in the ocean under various backgrounds. In this paper, the latest progress of in situ detection of dissolved methane and carbon dioxide in the ocean based on electrochemical, optical, mass spectrometry and biosensor technologies is reviewed, the working principle and performance of each sensor are introduced systematically, the application value and prospect of it are analyzed, and some suggestions for future research are put forward.