When a bamboo slip becomes dehydrated and driedup, it deforms and the characters on the slip became unrecognizable. That kind of bamboo slip is of little value for archaeological studies. This paper focuses on the restoration of the dehydrated and driedup bamboo slips unearthed from Haihun Hou tomb etc. By comparing the sizes, components and micro mechanisms of a bamboo case before and after treatment, it is found that the size of the bamboo case can be restored to 98% of its original size, although the chemical composition in the bamboo did change when the dehydrated and driedup bamboo case was soaked in solutions of alkali and surfaceactive agents for a period of time. This method can be used to restore dehydrated and driedup bamboo slips to a waterlogged condition. Moreover, the method does no damage to the characters on the slips.