A food vending machine has a food-preparing device and a storage device. The storage device is connected with the food-preparing device and has serving openings and a transmission mechanism. The transmission mechanism has multiple loading assemblies capable of moving along a transmission route. A food-serving method includes an ordering process, a preparing process, and a serving process. A consumer may choose later pick-up and optionally specify a pick-up time. Then, if the consumer chooses later pick-up but does not specify a pick-up time, the storage device serves the meal; if the consumer chooses later pick-up and specifies a pick-up time, the food-preparing device serves the meal, but the meal will be conveyed to the storage device after a pre-set time. Thus, a waiting time of the consumer may be reduced, and a formerly ordered but not-yet-picked-up meal may not interfere with a later consumer.