Disclosed is an air fryer capable of automatically setting cooking time. The air fryer capable of automatically setting the cooking time comprises a fryer body, a liner and a frying basket which is arranged in the liner. The fryer body comprises a three-dimensional cradle head, a distance measuring sensor, a weighing module, a voice module, a power module, a controller and an air frying module. The distance measuring sensor is an ultrasonic sensor or an infrared sensor, fixed on the three-dimensional cradle head, located over the frying basket and used for measuring all the distance values of all food material sampling points in the frying basket. The weighing module is located under the liner and measures the weight of the liner before and after food materials are placed in to obtain the weight G of the food materials. The controller calculates the volume V of the food materials and the weight G of the food materials, inquires a preset chart, reads the corresponding cooking time, turns off the air frying module when time is up, and sends a voice alarm. According to the air fryer capable of automatically setting the cooking time, the cooking time can be automatically adjusted according to different numbers of the food materials to avoid the situation that food is burnt because of being cooked too long, and therefore healthy cooking is achieved.