Abstract: Micro-electronic components encapsulated with the high-polymer matrix composites are easy to be affected with damp. In the process of welding, the temperature and moisture often cause delamination and fracture in electronic components. For moisture and heat-sensitive high polymer materials, when considering the problem of elastic breakdown induced by moisture and heat, the strain energy release rate at the crack tip can be expressed as an integral form. With FEM and by using the expression of energy release rate, the curves for the relationship of energy release rate versus the ratios of crack length to the thickness of the package are obtained at different welding temperature. The fracture of the electronic components is predicted through Comparing the experimental data of strain energy release rate.