The invention discloses a convex airflow distribution plate and a reactor thereof. The convex airflow distribution plate is formed by improving a flat-plate airflow distribution plate and comprises a protruding structure upwards protruding along the central axis and a bent structure formed by upwards bending the circumferential side of the convex airflow distribution plate. The protruding structure is a conical structure, a spherical structure or a protruding structure formed by inwards-concave two hyperboloids which are in symmetric arrangement. The convex airflow distribution plate is conducive to process gas entering from the bottom of the reactor to flow out through airflow holes, materials going down from the upper portion of the reactor and the process gas going up from the lower portion are enabled to contact uniformly and fully, and relatively stable air pressure is maintained; the airflow plate combines airflow balance, granular product fluidity and internal structure fatigue resistance and is simple in combined structure and convenient to mount and maintain, and a supporting member of the airflow plate is more reasonable in stress, high in stability and more safe and scientific in space layout, so that the reactor has high operation flexibility and can withdraw from reaction heat more swiftly, shell wall safety is protected, and service life is prolonged.