A stall diagnosis apparatus for a motor of an air conditioning actuator includes: a resistor connecting from a first door actuator of a Heating, Ventilation and Air Conditioning (HVAC) system of a vehicle to the ground; a resistor connection circuit connecting from a VCC power terminal to the resistor; a switch disposed on the resistor connection circuit; a first circuit and a second circuit branched from a motor connection circuit connecting from the VCC power terminal to a motor of the first door actuator through a motor driver and the resistor connection circuit, respectively; a current sensing circuit unit including an input terminal connected to the first circuit and the second circuit and outputting a current signal corresponding to a voltage value between the motor connection circuit and the resistor connection circuit; and a controller for controlling the motor and determining whether or not the motor is stalled.