Abstract: The cold storage of fruit and vegetable has higher request for the uniformity of temperature, relative humidity and air velocity.The air-cooler with uniform air supply duct can meet the condition of fruit and vegetable storage better.The authors chose a cold storage of apples as a research object and explored the velocity, temperature and relative humidity fields under two different conditions: one used the distribution system and the other did not.Then a combination of CFD (computational fluid dynamics) calculation and experimental study was carried out to further understand the complicated phenomenon of air flow and heat transfer in cold storage.A three dimension physical and numerical model for flow, heat and mass transfer inside the air-cooler(with uniform air supply duct)-cargo-air in the cold storage was developed.The k-ε turbulent model was considered as CFD model.The apple zone was regarded as porous medium zone.When the inlet temperature was 271.15K, inlet velocity was 8.48 m/s and inlet relative humidity was 90%, the velocity, temperature and relative humidity distributions were simulated by CFD software.The simulation results were validated by experimental results.The main instruments for experiment included thermal anemometer ZRQF-F30J and infrared thermometer EC-8399.The total amount of 16 measurement points were tested at following air-cooler inlet parameters: 271.15 K, 8.48m/s and relative humidity 90%, and the air supply system was a uniform air supply duct.The relative difference of the temperature between simulation value and experimental data at 13 measurement points was less than 15%, occupying 81.25% of total measurement points.The numerical results were in good agreement with the measured results.Simulation results showed that the maximum difference in temperature was 0.8 K for the cold storage equipped with a uniform air supply duct and 1.2 K the cold storage without uniform air supply duct.The maximum difference in temperature for the cold storage with uniform air supply duct was 33.33% lower than that without the uniform air supply duct.The maximum difference in relative humidity was 5% for the cold storage equipped with a uniform air supply duct, and 7% when the cold storage without uniform air supply duct.The maximum difference in relative humidity for the cold storage with uniform air supply duct was 28.75% lower than that without the uniform air supply duct.Further, the non-uniformity coefficient and air diffusion performance index(ADPI) were introduced to assess the fields.The total amount of 780 measurement points were selected, which were uniformly distributed and the step length of three coordinate directions was 1 m in the studied cold storage.Both of the non-uniformity coefficient and air diffusion performance index (ADPI) was computational by gathered velocity, temperature and relative humidity of every measurement points.When the uniform air supply duct was installed in the cold storage, the non-uniformity coefficient of air velocity was 22.65% lower than the cold storage without uniform air supply duct.The non-uniformity coefficient of temperature was 20% lower than the cold storage without uniform air supply duct.The non-uniformity coefficient of relative humidity was 22.73% lower than the cold storage without uniform air supply duct.The value of ADPI was 11.13% higher than the cold storage without uniform air supply duct.Thus, the air velocity, temperature and relative humidity fields were more uniform in the cold storage which had the uniform air supply duct.