The utility model discloses an active control ventilation system for false work vacant lot surface course. Traditional building's built on stilts ground structure is simple, limited and labyrinth between vented cavity under the built on stilts board, and ventilation condition is general, can not artificially control according to actual conditions. The utility model discloses an active control ventilation system for false work vacant lot surface course, wherein: the latticed metal of second keeps off the net gomphosis and leans on interior wall one side at the ventilation square pipe that admits air, and horizontal fixed mounting has discharge formula axial fan in the ventilation square pipe that admits air. The utility model has the advantages of: system structure is simple, construction convenience, realizes artificially controlling, improves indoor comfort level, construction difficulty, the low scheduling problem of standardization level have been solved to the structure of integraltype, have avoided simultaneously leading to the fact the damage to building bottom wall body, the setting keeps off the problem that can effectively solve the built on stilts layer of entering suchas snake, mouse and bring the potential safety hazard to the resident of netting at the latticed metal of ventilation hole both sides.