Abstract: The high-density polyethylene plastic buckets used for containing trichloroacetyl chloride solution foamed in a short time at the bucket body. According to the usage and structural characteristics of the high density polyethylene plastic buckets, they were analyzed by infrared spectrometer, X-ray diffractometer, thermal analyzer and other equipments. The results show that the foaming of the high density polyethylene plastic buckets was directly related to the calcium carbonate composition in the material of the plastic buckets. That the trichloroacetyl chloride contained in the bucket and its hydrolyzed products reacted with calcium carbonate in the material of the plastic buckets was the main cause for the foaming.