The best variety of apple tree rootstock in Yan'an, Shaanxi is M9T337. M9T337 is a virus-free M9 selection line and is a dwarf stock. It is the most widely used and most productive rootstock in developed countries in the fruit industry. This rootstock has brittle wood, short internodes, and shallow root distribution. It is mainly distributed in the soil layer of 20 to 60 centimeters. When the soil layer is deep, it has stronger soil fixation and needs to be cultivated on an erect support. It has good grafting compatibility with most apple varieties. Varieties grafted on M9T337 rootstock have the characteristics of early fruiting, easy flowering, extremely high yield, low temperature tolerance, less tillering, and uniform fruit size. If you plant it in the same year, it will bear fruit in the same year. Dwarf and intensive cultivation will become the main trend in apple cultivation in the future.