The invention provides a liquid nitrogen precooling device for fruits and vegetables. The liquid nitrogen precooling device comprises a self-pressurization liquid nitrogen bottle, a liquid nitrogen pipe, a nitrogen pipe, a nitrogen jet pump and a precooling chamber. A nitrogen outlet of the self-pressurization liquid nitrogen bottle is connected to a high-pressure gas inlet in the left end of the nitrogen jet pump by the nitrogen pipe, a liquid nitrogen outlet of the self-pressurization liquid nitrogen bottle is connected to a liquid nitrogen inlet in the upper end of the nitrogen jet pump by the liquid nitrogen pipe, an outlet in the right end of the nitrogen jet pump is connected with the precooling chamber by a first ventilating pipe, and the precooling chamber is connected to a gas suction opening in the lower end of the nitrogen jet pump by a second ventilating pipe. The liquid nitrogen precooling device has the advantages that the fruits and vegetables can be precooled without electric power, and accordingly the liquid nitrogen precooling device is particularly applicable to fruit and vegetable producing areas in remote regions; nitrogen can be recycled, and accordingly the liquid nitrogen utilization rate can be increased.