Abstract: According to the theory of CAD framework and software architecture, the computer aided FMECA software model was analysis and established. Firstly, the target of FMEA software and design strategy was discussed. And then data model of the product, failure mode, and result of FMECA was established using the OTO-D(Object Type Oriented Data model) semantic model. The software structure applying the technology of CFI(CAD Framework Initiative) and running environment were described in detail. Finally, the FMECA implement methods including the visualization of product hierarchy description and the FMECA result data query, the representation of data using relation model in database, the automation of the FMECA table filling and C_r calculating were discussed in detail.