A cradle head comprises an installation frame for installation of a photographing apparatus and a fastener (30) for fastening the photographing apparatus. The fastener (30) has a first end and a second end fitting with the installation frame. At least one of the first end and the second end of the fastener (30) is connected and fits with the installation frame by means of an adjustable structure. The adjustable structure can adjust a distance between one end of the fastener (30) provided with the adjustable structure and the installation frame. By using the adjustable structure to adjust the distance between the end of the fastener (30) provided with the adjustable structure and the installation frame, the fastener fits with the photographing apparatus, thereby achieving a better fastening effect, preventing loosening of the photographing apparatus, and ensuring a good photographing effect. Also provided are a cradle head assembly, and an unmanned aerial vehicle.