In order to study the juice cooling process after sterilization to obtain the accurate process and reduce the energy used in the cooling, the orange juice in can high temperature short time (HTST) sterilization process was calculated. The maximum temperature of juice in can was defined as 60°C. By using FLUENT, a kind of software which combines hydrodynamics, mathematics and computer technology, we were able to put different fluids into analog computation and numerical experiment to solve problems related to hydrodynamics. Orange juice cooling numerical experiment after HTST sterilization was carried out. The optimization cooling process was obtained: 20°C(293K),14 minutes;15°C(288K),13 minutes; 10°C(283K) ,13minutes; 5°C(278K), 12minutes and 0°C(273K), 12minutes. Using Carnot efficiency in Reverse Carnot cycle, the energy consumption was: 288W, 325W, 348W, 391W, 417W in accordance. And in the result, the optimized process was : 20°C(293K),12 minutes.