To explore the differences in seed morphological characters and identify the chemical constituents of Tartary buckwheat varieties of Chuanqiao No.1, Xiqiao No.1, Miqiao No.1 and Di ku, the morphological differences of different varieties Tartary buckwheat were observed, and the 1 000-grain weight and water content were measured. Ultrahigh performance liquid chromatography-quadrupole-orbitrap HRMS (UPLC-Q-Orbitrap HRMS) was used to quickly identify the chemical constituents of four varieties of Tartary buckwheat. As results, there were obvious differences in seed shape and color among the four buckwheat varieties. Chuanqiao No. 1 was black and long cone-shaped, while the other three buckwheat varieties were short cone-shaped. The seed coat of Miqiao No. 1 was beige, and the seed coat of Di ku was gray; at the same time, the 1 000-grain weight and water content of four buckwheat varieties were also significantly different. In addition, the overall ion flow peak shapes of the four varieties of Tartary buckwheat were basically the same except for individual components. A total of 27 compounds were identified, including flavonoids, amino acids, alkaloids and so on. The results can provide a comprehensive theoretical basis and reference for the selection and breeding of excellent varieties of Tartary buckwheat and the optimization of quality control indexes. Furthermore, it has a certain guiding significance for further developing and utilizing the resources of Tartary buckwheat.