The invention relates to the field of medical metal materials, and discloses an anastomotic nail and a preparation method and an application thereof. A material of the anastomotic nail is a magnesiumalloy, and with the total amount of the magnesium alloy as a benchmark, the magnesium alloy contains, by weight, the following elements: 0.01-3% of Al, 0.01-1% of Sn and 95-99% of Mg. The anastomoticnail has the characteristics of both high yield strength and appropriate degradation rate, appropriate specific strength and specific stiffness, and good bio-safety, can ensure that a sutured human tissue or organ is free from infection and has no any damage, and is expected to achieve large-scale practical clinical applications.