The invention discloses a network-based unmanned self-service food selecting system and an operation method thereof. The system comprises an unmanned food selling dining table, a network platform system and a mobile phone terminal system. According to the invention, a flexible isolation mechanism is used for isolating eaters and foods, thereby ensuring that the food is clean and safe; eaters select food according to personal preference, and are capable of taking the food away after automatic charging and settlement are performed according to the type, weight and unit price of the selected food, thereby achieving unattended operation; the unmanned food selling dining table records all food selecting operation and transmits data to the network platform system for data processing; eaters arecapable of searching the type, the weight, the caloric values, and the nutritional ingredient information of the food by use of mobile phones; and scientific calculation is performed on body conditions and exercise quantity of eaters and reasonable diet advices are given out. In this way, users are capable of make comments on the food; the system is capable of gathering sales volume, cost accounting and sales speed of each good; and precise data support is provide for canteen operation.