Based on geometric shape and physics parameters of longan fruit, the mechanical model of single longan was established. The module of elasticity of longan flesh was determined by means of comparing the calculated results on the mechanical model with the experimental results. By finite element analysis on longan under the compressed load with the pedicel and middle, the stress distribution of inner longan was obtained. The results showed the maximal tensile stress was the main factor causing the macroscopic breakage form of longan skin.