A disassembly wooden box device used for soil monolith collection and its applying procedure in field were described in this paper. Compared with the conventional wooden box device, this new device has the following advantages: the top and bottom planks are interchangeable, which simplifies the making process of the device and make it more effectively and flexibly in choosing the more suitable soil observation surface for indoor monolith processing. The fixation measure is simpler and more efficient, and the device is more firmly fastened. No nail is needed in the whole process which can prevent operators from being injured. The top plank, bottom plank and plank frame can be freely and easily disassembled. In general, the device has simple structure, convenient making process, low cost and reusable.