Abstract: In order to further clarify the natural gas exploration potentials and distribution of favorable targets, analyze the outstanding problems and improve the exploration theories in onshore deep and ultra-deep formations in China, the exploration progresses and resources were reviewed, the geology, key factors on reservoir formation and potentials of natural gas resources were classified and evaluated. Our study shows that: (1) 10 foreland thrust belts and slopes (i.e. Kuqa, West Sichuan, South Junggar, etc.) developed in the piedmont zones of the superimposed basins in mid-western China are key exploration zones in foreland thrust belts; (2) the paleo-uplifts and slopes, intracratonic rifts and platform margin reef beaches in the Ordos Basin, Sichuan Basin and Tarim Basin developed on three major cratons (North China, Yangtze and Tarim) are important deep and ultra-deep marine carbonate rock zones; (3) the deep paleo-uplifts, slopes and bedrock buried hills in the Songliao Basin and the Bohai Bay Basin are deep and ultra-deep targets in Mesozoic-Cenozoic rifted basins; and (4) others like deep and ultradeep volcanic rocks are future exploration targets. More problems should be solved, and more basic researches should be conducted related to exploration of deep and ultra-deep natural gas in China.