Mesoscale eddy is ubiquitous in the world ocean. Its energy is an order of magnitude larger than the large-scale general ocean circulation playing an important role on the mass and energy transports, and global climate change. Due to lack of in-situ observations, eddies are mainly observed by utilizing satellite altimeter data. Its size, distribution, intensity, and mass and energy transports can also be estimated based on sea surface height data. However, the vertical structure of the mesoscale eddy can’t be captured by remote sensing, which led to large error for estimation of heat and energy transports by mesoscale eddy. Now we know little about the three-dimensional structure of the mesoscale eddy. To design an unmanned observation system to investigate the three-dimensional structure of the oceanic mesoscale eddy is necessary. This system will integrate and apply the advanced technology (such as unmanned ship platform, ocean automatic profile observation) to observe the three-dimensional structure and temporal-spatial variation of the mesoscale eddy, which will enhance understandingSof the material and energy transfer by the mesoscale eddy.