Abstract: Jizhong Sag of Bohai Bay Basin has good geological conditions for buried hill hydrocarbon accumulations and abundance. A series of large and medium-size buried hill oil and gas fields (reservoirs), such as Renqiu buried hill, have been discovered. With the oil and gas exploration degree improved and the exploration technology upgraded, the active efforts for initial exploration of subtle deep buried hill and buried hill inner curtain hydrocarbon reservoirs led to discovery of a number of subtle abundant high-yield buried hill hydrocarbon reservoirs, such as Niudong-1 super-high temperature deep buried hill hydrocarbon reservoir and Chang-2 buried hill inner-curtain hydrocarbon reservoir, revealing a bright prospect for exploration of this field. Less influenced by the buried depth, the carbonate rock deep buried hill reservoir is good for its physical properties and characterized in early hydrocarbon infill, long-period infill and high-pressure infill, with favorable conditions for accumulations. There were a number of reservoir-cap assemblages in the buried hill inner curtain, forming a variety of sourcemountain contact patterns, conducting systems, and coupling relations of conductivity and physical properties of buried hill inner-curtain reservoir to control hydrocarbon accumulations. Discovery of subtle deep buried hill and buried hill inner-curtain hydrocarbon reservoirs is benefited mainly from ideological emancipation, careful study, creative pattern and technological progress.