The invention relates to an efficient special SNCR denitration device for the petrochemical industry. The device comprises a flue, a denitrfying agent system, a dilution water system, an air compression system and a cooling water system. Several SNCR denitration spray guns are arranged in the flue. The cooling water system and the air compression system are both connected to the SNCR denitration spray guns through distributors. The denitrfying agent system and the dilution water system are both connected to the SNCR denitration spray guns through a mixer and a denitrfying agent distributor. The SNCR denitration spray guns are penetrating-type, and each of the SNCR denitration spray guns is equipped with multiple nozzles. Thereby, spray cover area can be guaranteed, distribution of the denitrfying agent is uniform, the denitration efficiency is high, ammonia escape amount is less, and corrosion to rear equipment is effectively reduced. The SNCR denitration spray guns and casing pipes are sealingly fixed by a movable buckle method, which facilitates disassembly and assembly of the SNCR denitration spray guns. The casing pipes are filled with a thermal insulation material, thus reducing heat loss at holes of the casing pipes.