Abstract: The phase-field model which coupled the concentration field and phase field is applied to simulate microstructure evolution during crystal growth of juice binary in 2-D, exploring the process of fruit juice crystallization. In this paper, the influence of interfacial thickness on ice crystal growth morphology and solute distribution was investigated, and a reasonable value of interfacial thickness was estimated. The simulated results showed that the interfacial thickness had positive and negative effects on ice crystal morphology.In the range of disturbance, the secondary dendrite became more and more developed and the dendrite tip was also more sharper with the increase of the interfacial thickness. Outside the range of disturbance, the secondary dendrite didn't grow, and the principal axis of the dendrite became thin and even some disappeared. The growth speed of ice crystal would increase and the tip radius would decreased with the increase of interfacial thickness.When the interfacial thickness was around 3dx, the best simulation result of the dendrite morphology and high calculation efficiency could be obtained.