Cushioning material for packing and making method thereof

The present invention relates to a cushioning material for packing, which in particular is light in weight and doesn't produce harmful gas after burning and is strong in water solubility and can be treated by water flow, and is suitable for the packing of waste treatment free from environmental pollution. Its preparation method is as follows: the plant powdered particles obtained by refining plant powder is passed through the processes of heating, pressurizing and rapidly depressurizing, and after their valume is expanded, those are made into a lot of plant powdered balls, and then those plant powdered balls can be bound together or can be used in the form of their original shape to match the contour of thing to be packed, and caved, so that the invented packing cushioning material can be made up.