Abstract: The return of biochar to farmland is guided by the “dual carbon” goal, achieving carbon fixation and emission reduction,improving soil quality, protecting water quality, and increasing crop yield and quality, which is of great significance for the development of green agriculture. Corn straw biochar was prepared using an electric heating furnace under different pyrolysis final temperatures(300℃, 500℃, 800℃), and its physicochemical properties such as thermal weight loss, specific surface area,microstructure, and characterization were studied. Subsequently, biochar returning experiments were conducted. The results showed that the higher the final pyrolysis temperature, the more complete the pyrolysis of biochar; After returning biochar with a final temperature of 500℃ to the field, potatoes have the highest water absorption, the highest number of aboveground stems, and the highest average height of aboveground stems, resulting in the most ideal return effect.