The invention discloses a flour mixing device of a deep-fried dough stick machine, and relates to the field of food processing. The flour mixing device includes a mixing mechanism, a dough kneading mechanism is arranged at the bottom of the mixing mechanism, a leavening cabin is connected to the right side of the dough kneading mechanism through a lifting machine, an extrusion machine is fixed tothe bottom of the leavening cabin, a discharging mechanism is arranged at the right end of the extrusion machine, a conveying machine is arranged below the discharging mechanism, a composite shaping mechanism is arranged at the middle of the conveying machine, a stretching detachment mechanism is arranged on the right portion of the conveying machine, and a deep-frying device is arranged at the bottom of the right end of the conveying machine. By adopting the flour mixing device of the deep-fried dough stick machine, a manual deep-fried dough stick making process can be stimulated, after wateris automatically added into flour and is mixed with the flour to make dough, the dough is kneaded, leavened, pressed, shaped and then stretched, finally, the dough is deeply fried, manual labor is greatly reduced, the mouthfeel of deep-fried dough sticks is ensured, the deep-fried dough sticks are efficiently and rapidly made, and the flour mixing device is suitable for being used in breakfast stores.