The invention discloses a vertical power electronic device based on a floating gate-drain composite field plate. The vertical power electronic device comprises a Schottky drain (13), a substrate (1), a drift layer (2), an aperture layer (3), two symmetrical current blocking layers (4), a channel layer (6), a barrier layer (7), a cap layer (8) and a grid (10) from bottom to top; an aperture (5) is formed between the two current blocking layers (4); two sources (12) are deposited at two sides of the barrier layer; two injection areas (11) are below the two sources; a passivation layer (15) wraps all areas, except the bottom of the Schottky drain, wherein a floating gate-drain composite field plate (14) is manufactured in the passivation layer at two sides; the floating gate-drain composite field plate is composed of a gate field plate, a drain field plate, multiple gate floating field plates and multiple drain floating field plates; and a two-stage step structure is adopted in the current blocking layers. The vertical power electronic device disclosed by the invention has high breakdown voltage, simple process, low conduction resistance and high yield, and can be used for power electronic systems.