The ABAQUS software was applied to finite element structure analysis of a cassette strain-gauge balance in NF-3 wind tunnel located at Northwestern Polytechnical University. Based on this analysis, the design of the flexible link structure was improved, at the same time; comparison between the two design schemes was made. The result shows that with the improved structure, the whole stiffness of the balance was strengthened; the interference of the each load, particularly on the axial force was reduced. Finally, the sub-model technical was used for precise analysis of the serious force points and checking the balance strength. All the above analyses improve the design efficiency and the success rate in the process of cassette balance design, which has a good engineering application value.