The fluctuating characteristic of the metamorphosed basement of Precambrian era and the depth change of sedimentary cover are of great importance for geological structure study and energy and resources exploration. Some magnetic difference is present between the metamorphosed basement of Precambrian age and sedimentary cover, which permits geophysical study of magnetic basement depth using aeromagnetic data. This work is based on the magnetic basement depth data acquired by AGRS in the past more than 30 years, which has conducted aero geophysical surveys in China mainland, covering more than 30 basins and areas, and compiled the China's land magnetic basement depth map on the scale of 1 : 1000000 with transforming all the data into the same coordination system and scale. The study has revealed that using 105 degrees E line as the boundary, the covers have large thickness in sedimentary depression areas of western China, and are mainly distributed in the Tarim basin, Junggar basin, Qaidam basin and Tibetan area. Meanwhile, in eastern China, mainly distributed in the Songliao basin, Erlian basin, Ordos basin, basin of southern part of North China, Sichuan basin, South Yellow Sea-Subei basin, the covers have relatively small thickness in sedimentary depression areas, whose largest thickness is located in the southwest of the Sichuan basin and the western edge of Ordos basin. These research achievements reveal the characteristics of the metamorphosed basement of Precambrian age and the depth change of irruptive rock bodies with certain scales, and reflect sedimentary covers' thickness and status. In terms of the achievements mentioned above, one can intuitively understand the depths and scopes of various types of sedimentary basins and sedimentary depression areas, which provide direct evidence for search for oil and gas reservoirs on the basements.
