A staggered fin array has a plurality of dissipation fins disposed upright on a substrate. Each dissipation fin has at least one staggered structure at one side or on opposite sides thereof. The staggered structure has two stair structures. Each stair structure has many step surfaces parallel to the airflow direction. An interval surface is formed between adjacent step surfaces. The interval surface is designed as an opening. No more than two leading ledges, formed by the openings, are formed in a single airflow route.