Near-space is recognized as the altitudes between 20 kilometer (km) and 100 km. The thinness of the atmosphere makes it difficult for satellites and airplanes to operate there. However, the vehicles operating in near-space offer several advantages over satellites and airplanes. These advantages provide potential for specific remote sensing applications. In this paper, the near-space vehicle-borne millimeterwave radiometer is designed for regional ocean remote sensing. One conceptually design system is investigated, along with the performance analysis of detection range and imaging sensitivity. It is shown that the near-space vehicle-borne millimeterwave radiometer can efficiently overcome the shortcoming of spaceborne radiometer in spatial resolution.