The utility model discloses a denitrification facility's phase -change thermal catalytic unit and the denitrification facility who has it, phase -change thermal catalytic unit includes: the base member has the packing chamber in, it has phase -change thermal spare to fill the intracavity packing, is equipped with the selective catalyst layer on the surface of base member. According to the utility model discloses a phase -change thermal catalytic unit for denitrification facility, combine the phase -change thermal technique with the SCR technique, form a longer constant temperature environment in the flow direction of the flue gas in denitrification facility's combustion chamber, effective catalytic reaction zone's length has prolonged, and then the dwell time of NOx in catalytic reaction zone has been prolonged effectively, make NOx fully to take place the reaction with selective catalyst, denitration efficiency has greatly been improved, NOx's emission has been reduced, the environment has been protected effectively, the pollution to the environment has been reduced. Simultaneously, can preheat low warm air through phase -change thermal catalytic unit, make it reach suitable temperature to improve combustion efficiency.