Over the past years, there are many studies discusses different modes of die cracking and improvement. Die cracking is one of the crucial issues that influence the reliability of flip chip assemblies. Die cracking depends on a combination of several factors, such as residual bending stresses generated in the package due to mismatches in the coefficients of thermal expansion(CTE) of the various materials in the assembly or wafer dicing process . In this study, the stresses in the chip of a FCBGA (Flip-Chip Ball Grid Array) induced by the temperature raising and by the mechanical load of different pressures on an automatic test handler are investigated by using commercial finite element software ANSYS, while the FCBGA is subjected to the high temperature electrically test. The causes and precautions corresponding to the die cracking are studied in order to improve the reliability of products.