An automatic milk preparing device, characterized in that the automatic milk preparing device comprises: a microcontroller, which is fixed in the automatic milk preparing device for controlling the operation of the automatic milk preparing device; a powder box, which is connected with the microcontroller and provided with a powder output gate in the front of the powder box for controlling the powder to be added according to the signal from the microcontroller; a water tank, which is connected with the microcontroller for controlling the water to be added according to the signal from the microcontroller; a stirring structure, which is fixed below the powder output gate, connected with the water tank through a first water pipe, and provided with a milk outlet at the lower part of the stirring structure; and a weight measuring structure, which is fixed below the stirring structure and connected with the microcontroller for laying a milk bottle, weighing water and/or milk powder in the milk bottle, and feeding the result of weight back to the microcontroller; wherein, the milk powder and water are fed into the stirring structure from the powder box and the water tank respectively for stirring, and flow into the milk bottle through the milk outlet of the stirring structure, and the microcontroller controls the weight of water and/or powder to be added for the next time according to the weight of water and/or milk powder in the milk bottle; the microcontroller controls the water tank to add water for the first time, and the weight measuring structure weighs water in the milk bottle and feeds the result of weight back to the microcontroller; the microcontroller controls the powder box to add powder for the first time and the water tank to add water for the second time, and the weight measuring structure weighs milk liquid in the milk bottle and feeds the result of weight back to the microcontroller; and the microcontroller controls the powder box to add powder for the second time and the water tank to add water for the third time; the microcontroller calculates the flowrate of water to be added according to the time of the first water addition and the weight of water in the milk bottle; and the microcontroller controls the amount of water to be added by the water tank for the second and third times according to the flowrate of the first water addition; the microcontroller calculates the flowrate of powder to be added according to the time of the first powder addition by the powder box and the weight of milk powder in the milk bottle; and the microcontroller controls the amount of powder to be added by the powder box for the second time according to the flowrate of the first powder addition; the addition of the powder and water can be performed for several times. a microcontroller, which is fixed in the automatic milk preparing device for controlling the operation of the automatic milk preparing device; a powder box, which is connected with the microcontroller and provided with a powder output gate in the front of the powder box for controlling the powder to be added according to the signal from the microcontroller; a water tank, which is connected with the microcontroller for controlling the water to be added according to the signal from the microcontroller; a stirring structure, which is fixed below the powder output gate, connected with the water tank through a first water pipe, and provided with a milk outlet at the lower part of the stirring structure; and a weight measuring structure, which is fixed below the stirring structure and connected with the microcontroller for laying a milk bottle, weighing water and/or milk powder in the milk bottle, and feeding the result of weight back to the microcontroller; wherein, the milk powder and water are fed into the stirring structure from the powder box and the water tank respectively for stirring, and flow into the milk bottle through the milk outlet of the stirring structure, and the microcontroller controls the weight of water and/or powder to be added for the next time according to the weight of water and/or milk powder in the milk bottle; the microcontroller controls the water tank to add water for the first time, and the weight measuring structure weighs water in the milk bottle and feeds the result of weight back to the microcontroller; the microcontroller controls the powder box to add powder for the first time and the water tank to add water for the second time, and the weight measuring structure weighs milk liquid in the milk bottle and feeds the result of weight back to the microcontroller; and the microcontroller controls the powder box to add powder for the second time and the water tank to add water for the third time; the microcontroller calculates the flowrate of water to be added according to the time of the first water addition and the weight of water in the milk bottle; and the microcontroller controls the amount of water to be added by the water tank for the second and third times according to the flowrate of the first water addition; the microcontroller calculates the flowrate of powder to be added according to the time of the first powder addition by the powder box and the weight of milk powder in the milk bottle; and the microcontroller controls the amount of powder to be added by the powder box for the second time according to the flowrate of the first powder addition; the addition of the powder and water can be performed for several times.