Heat rejection, dust collection and ventilation structure of heavy-pollution closed plant

The invention provides a heat rejection, dust collection and ventilation structure of a heavy-pollution closed plant. A plant mechanism is totally closed. A roof structure comprises a left roof (1), a right roof (4) and a sinking type roof (2) located between the left roof and the right roof. A blast furnace corresponds to the sinking type roof (2) in position. A left trough corresponds to the left roof (1) in position. A right trough corresponds to the right roof (4) in position. The sinking type roof (2) is provided with a plurality of ventilation openings (3), and heat is discharged out of ventilation openings (3) through a roof draught fan. The left roof (1) and the right roof (4) at the upper portion of the left trough and the upper portion of the right trough are used for controlling hot smoke below the left roof and the right roof. The left roof and the right roof are provided with roof covers (5), and the hot smoke can be discharged conveniently. According to the structure, the post temperature of the plant can be effectively reduced, dust can be effectively captured, and smoke is prevented from overflowing.