The invention discloses an assembly type intelligent air sterilizing and disinfecting device and application thereof. The device comprises a ventilating duct, an internal circulation draught fan, a control system, a multiple filtering sterilizing and disinfecting system and an external discharge draught fan, and the internal circulation draught fan, the control system, the multiple filtering sterilizing and disinfecting system and the external discharge draught fan are sequentially arranged on the inner wall of the ventilating duct from top to bottom. The pipe wall of one side of the ventilating duct is provided with an upper air inlet, an upper air outlet and a lower air inlet, and pipe walls of the opposite sides are provided with lower air outlets; the upper air inlet is located above the internal circulation draught fan, the upper air outlet is located at an air outlet of the internal circulation draught fan, the lower air inlet is located above the multiple filtering sterilizing and disinfecting system, and the lower air outlets are located at an air outlet of the external discharge draught fan. The multiple filtering sterilizing and disinfecting system comprises an initial efficiency filtering net, a high pressure electrostatic device, an efficient filtering net, an ozone decomposition net and an ultraviolet lamp. The invention further provides an inpatient ward comprising the above device. By means of the device, reasonable airflow texture, efficient sterilizing and disinfecting, the simple dismounting and mounting manner and high comfort can be achieved.