The utility model relates to an auxiliary device in machining, in particular to an adjustable tray of an automatically ascending and descending feed bin matched with a numerical control machine. The adjustable tray of the automatically ascending and descending feed bin comprises a roller fixed below a bottom plate, guide posts and a lifting supporting plate which are installed on the bottom plate. The adjustable tray of the automatically ascending and descending feed bin is characterized in that a nut is fixed on the bottom plate, locating holes are evenly distributed on a circle located on the bottom plate and taking the center of the nut as the circle center, a rotating block is fixed on each locating hole in rotating mode through a locating pin, a guide post is fixed on each rotating block, semicircular grooves are evenly distributed on the plate-shaped lifting supporting plate and an adjusting tray with the locating holes serving as circle centers, the radius of each semicircular groove is the center distance between the locating pin of the rotating block which can be fixed in rotating mode and the guide post fixed on the rotating block, the lifting supporting plate and the adjusting tray are sequentially sleeved on the guide post from top to bottom, and the adjusting tray is fixed on the bottom plate through a bolt matched with the nut. The adjustable tray of the automatically ascending and descending feed bin has the advantages of being suitable for parts of different sizes, high in locating accuracy, compact in mechanism, convenient to maintain and the like.