Vertical drop in packaging electronic instruments was simulated using theory and finite element analysis to correctly assess the influence drop impact on reliability of electronic instruments, determine logical packing parameters and design process, guide transportation and experiment scientifically. The changing law of maximal acceleration and maximal displacement of electronic instruments with drop height and elastic modulus of buffer under vertical drop condition was obtained. The maximal height of products in storage and transportation was determined. Logical packaging design process was obtained. The purpose was to provide reference for packaging design, full-scale experiment and safety of storage and transportation.