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Adjusting the concentration of oxygen is a key factor in maintaining the quality of fresh products in transportation equipment with controlled atmosphere (CA).Liquid nitrogen injection was proved to be an effective way for decreasing the oxygen concentration, but it also has great effects on the temperature and pressure in the container.Therefore, the effects of liquid nitrogen injection on the volume fraction of oxygen and temperature distribution in a container based on differential pressure principles with CA were investigated in this study.The container consisted of a pressure room, fresh room, fan, liquid nitrogen-vaporizing coil, air duct, products, and other parts.The geometry of this model was created by Pro/E and the mesh was generated in ICEM CFD.Grid independence was studied to test the quality of the meshes and choose a proper mesh number for this model.A 3-D model was built, and the air flow, heat, and mass transfer in the process of liquid nitrogen injection were simulated by changing the velocity in the outlet of the air duct, including 2 m s-l, 4 m s-l, 6 m s-l, and 8 m s-1.The distribution of the velocity, temperature, volume fraction of oxygen in the container, and injection time under all the air duct velocities were computed by FLUENT.The initialization conditions were set according to the environment that the pre-cooling of the container and products were finished.An UDF was made to investigate the effect of the latent heat of liquid nitrogen, by which the conditions of air in the outlet can be transmitted to the inlet.Results across the different simulations were compared and analyzed.A test platform was built to verify the simulation results.The simulation results of 8 m s-1 were compared to the experimental data.The following conclusions were drawn: the time of liquid nitrogen injection increases as the air duct velocity increases, and the oxygen decreasing times are about 24, 26, and 28 min, respectively.The effect of different air duct velocities on the distribution of the oxygen volume fraction is not significant that the deviation between the maximum and minimum value is less than 0.1% under various air duct velocities.The uniformity of the temperature distribution and the temperature in the outlet of the clapboard in a container is improved by improving the air duct velocity, such that the standard deviations were 1.882, 1.256, and 0.732, respectively.The temperature difference on the surface of the products and in the symmetry section of the container decreases as the air duct velocity increases, when the air duct velocity is 4 m s-1, the lowest temperature is below 0 ℃.The values at the monitoring points during the process of liquid nitrogen injection were record and compared with the test values.The difference between the simulation and experimental results was less than 1 ℃.The results provide a detailed understanding of air transport and its influences on temperature, oxygen volume fraction, and injection time, which will be useful for the design and optimization of transportation containers for fruits and vegetables with controlled atmosphere.