On the basis of the study of coal petrology, coal organic chemistry and plate tectonics on the north margin of the East Qinling erogenic belt, this paper asserts that the formation of coal-rank patterns in the Late Paleozoic coal measures in the area might not result entirely from regional burial metamorphism or magmatic thermal metamorphism, but mainly from the abnormal thermal metamorphism probably caused by the plate tectonism on the south margin of the North China plate. The heat for metamorphism of coal-bed II1 was derived dominantly from the differentiation of the lithospheric thermal structure in the foreland basin due to the adjustment of the litho-spheric structure caused by long-continued plate subduction and A-type collision. The metamorphism of coal bed II1 can be divided into three stages; (1) Before the Middle Triassic, coal underwent mainly regional burial metamorphism and attained about gas-fat coal. (2) From the Late Triassic to Jurassic, coal underwent high-temperature and high-pressure metamorphism owing to thermal anomaly caused by plate tectonic movement, and was metamorphosed to about anthracite or meta-anthracite. (3) In the Yanshanian movement, in some areas, coal underwent small-scale magmatic thermal metamorphism and was metamorphosed to blind coal. Thus the superimposi-tion of coal ranks of different metamorphic orgins formed in three different stages gave rise to the present patterns of coalification.