The invention discloses a stomach tube structure free of flow guiding. The structure includes a liquid inlet flow-guide tube, a liquid outlet flow-guide tube and an aspirator. The liquid inlet flow-guide tube and the liquid outlet flow-guide tube are in an L shape, the end portion of the liquid inlet flow-guide tube is provided with an liquid inlet, the end portion of the liquid outlet flow-guide tube is provided with a liquid outlet, and the liquid inlet flow-guide tube and the liquid outlet flow-guide tube are fixedly connected. An aspirator head and a push handle are arranged on the aspirator, the aspirator head is connected with the liquid inlet flow-guide tube and the liquid outlet flow-guide tube in an inserting mode, the push handle is connected with the aspirator through a piston, and the aspirator head and the aspirator are integrally formed during manufacture. The outer walls of the liquid inlet flow-guide tube and the liquid outlet flow-guide tube are provided with scale lines, and both the liquid inlet flow-guide tube and the liquid outlet flow-guide tube are rubber hoses. The aspirator is a negative pressure device and electrically connected with an external device. The structure is simple in structure and convenient to use, introducing of a cleaning agent and discharge of food are carried out in different tubes, pipe blocking is avoided, and repeated intubation is avoided.