Abstract: A warehouse system including a temporary storage device and a stacking crane is disclosed. The stacking crane includes a rack and a goods support. The rack includes three sensors. The temporary storage device includes a lifted support and a roller support. The goods support, the lifted support and the roller support may be lifted vertically between its high level and low level. The temporary storage device includes three reflective plates arranged according. to the locations of the third high level of the roller support, the second high level of the lifted support and the lifted support. In addition, three sensors are configured to sense the three reflective plate and determines if the stacking crane has to be shut down according to the sensing results. The warehouse system is capable of preventing the stacking crane from crash accidents.