Abstract: An Inconel 625 alloy with high aluminum content and a preparation method thereof are provided. The alloy includes following components by mass percentage: chromium 5˜13%, ferrum 5%, niobium 4.15%, molybdenum 10%, aluminum 5˜9% and a rest is nickel. The preparation method includes: step (1): weighing reactive materials according to a preset ratio and putting the reactive materials into a planetary ball miller for ball milling; step (2): pressing the ball milled reactive materials into a cake-shaped slab; step (3) putting the cake-shaped slab into a reactor and putting an igniter on the cake-shaped slab, then adding the reactor with protective gas, heating up until a self-propagating reaction occurs in the reactor, thereby obtaining a base alloy; step (4): performing secondary smelting on the base alloy to obtain an ingot; step (5): performing a solution treatment on the ingot to obtain the Inconel 625 alloy with high aluminum content.