The invention provides a detector which is used for function debugging, operational parameter detection and failure monitoring of an inverter air conditioner. The detector comprises a central processing unit, a host computer communication circuit, a nixietube display circuit, a button selective circuit, a communication port and a communication line group; the nixietube display circuit and the button selective circuit are connected with the central processing unit; the central processing unit is connected with a host computer through the host computer communication circuit and the communication port; and the central processing unit is connected with the electric control system of the inverter air conditioner through the communication line group. By applying the invention, the operational frequency of the inverter air conditioner, the wind speed of a DC blower, the divergence of an electronic expansion valve and the switching on/off of a four way valve can be set conveniently and quickly, so that the parameter debugging can be facilitated during the process of the development of the inverter air conditioner. Furthermore, by employing the invention, the operational parameters of the inverter air conditioner, including the operational frequency, the target frequency, various temperature sampling values, and the rotating speed of the blower, can be observed, and the data can be displayed in the form of a curve. In addition, the operational failure of the inverter air conditioner can be observed by applying the invention, and the information about the latest ten shutdown incidents is accessible.