Abstract: 2.5D packaging, with advantages of heterogeneous integration and low cost, is a key development direction for next-generation integrated circuits. About 20% of the failures in electronic devices result from shock and vibration, making it important to analyze the dynamic characteristics of 2.5D packaging under drop impact. Taking a certain 2.5D package as an example, ANSYS/LS-DYNA, combined with the Input-G method, was used, with solder joints modeled by both a linear elastic model and a strain-rate dependent Johnson-Cook constitutive model to simulate the transient dynamic response of 2.5D packaging. Underfill materials were introduced to enhance solder joint reliability, and the effects of acceleration amplitude and pulse duration on reliability were analyzed. The results show that the solder joint stress with the Johnson-Cook model is lower than that with the linear elastic model, and increasing underfill material significantly improves solder joint reliability, with larger fill areas yielding better results. Additionally, higher acceleration amplitude and pulse duration reduce solder joint reliability.