Dissolved methane Seepage across the sediment-water interface is not only sign of the seabed gas hydrate,but also the release pathway of its decomposition.Due to its impact on marine environment and global change,the attention of people is increasing.The in situ and flux estimation are the keys to understanding the science problem above.There are two mature observation methods:① measurements of seepage flow rate,with the indoor analysis of methane concentration;②continuous sampling techniques in benthic chamber,with the indoor analysis of methane concentration,the former is sensitive to changes in seepage rate,while the latter has a higher accuracy.With the development of methane sensor technology, in-situ measurement methods will improve the accuracy of flux measurements,the time span and temporal resolution greatly.Methane sensor can be mounted on a mobile observation platform,measure the micro scale profile of methane concentration and the turbulence at the same time in the benthic boundary layer, not only can characterize the fine changes in the methane concentration and seepage flux,but in opened environments can minimize the disturbance and the chemical changes.In addition,cold seep species have been widely used to extend the measurement of individual stations to the whole seep system.Researchers have studied on the seepage fluxes of several cold seep system,in one single system,nearly 6*10~3~1.35 *10~7 mol methane was released by dissolved form per year,and seepage changes with time and space greatly.Currently,it is hard to extend the flux of a single system to a long time spat or greater regional, becoming one of the bottlenecks in the research on methane reservoir,the global carbon cycle and climate change.