In this paper, we present the sensor fusion of a quad rotor aircraft. There are two main applications examined in this study, namely, gesture control and object detection. In gesture control, we can use hand and gesture to control the quadcopter instead of a traditional joystick. In the second application, the quadcopter can be applied to detecting an object surface automatically. The quadcopter can fly along an object to identify its color and circle around the object from a high altitude to a low altitude. If an abnormal area of the object is detected, the quadcopter will hover at that position, and the inspector can determine whether the object needs to be repaired through the images transmitted from the quadcopter. In addition, a voice broadcast system is integrated in the quadcopter, which can report the current status of the quadcopter. The inspector does not need to pay attention to the quadcopter and only needs to listen to the speaker. Ultrasonic sensors with a fuzzy logic system are applied to automatic circling and descending flight control.