The invention discloses an integral pyrolysis device and a pyrolysis process for ammonium chloride based on cross flow heat exchange. The pyrolysis device comprises a chlorine-releasing section reaction chamber and an ammonia-releasing section reaction chamber which are arranged in parallel, wherein each reaction chamber comprises a plurality of vertical material channels; a flue gas chamber for cross-flow recuperation with each material channel is arranged between every two adjacent material channels; a solid-phase material outlet is formed in the bottom of each material channel; a solid phase material inlet and a gas phase outlet are formed in the top of each material channel; a water steam inlet is also formed in the bottom of each material channel of the chlorine-releasing section reaction chamber. According to the pyrolysis device disclosed by the invention, the chlorine-releasing section reaction chamber and the ammonia-releasing section reaction chamber are spliced together to combine into an integral pyrolyzer; high-temperature flue gas transversely flows through and sequentially provides heat for a chlorine-releasing reaction and an ammonia-releasing reaction through cross-flow recuperation. According to the pyrolysis process disclosed by the invention, particles in the reaction chamber are enabled to be in homogeneous fluidization, bubbling fluidization and turbulent fluidization states by adopting proper particle size and operation speed, and stable operation and product quality of the reactor are guaranteed.