The invention relates to a re-crystallization preparation method of bamboo salt and belongs to the field of a health-care product. The method comprises the following process steps of: preparing fresh bamboo juice: baking fresh phyllostachys pubescens which is cut into small blocks and putting the blocks into a water bath to be immersed by ethanol or hot water; preparing primary bamboo salt: adding the fresh bamboo juice into table salt without iodine and an anti-caking agent and mixing uniformly; carrying out re-crystallization to prepare the bamboo salt: adding the primary bamboo salt into each biennial phyllostachys pubescens section with the length of 50-60cm and reserved with a bamboo section; sealing each opening of the biennial phyllostachys pubescens section by deep yellow mud with the depth of being less than 5m; adding into a high-temperature smoldering furnace to carry out high-temperature calcination in a step temperature-raising manner to carry out re-crystallization reaction; and preparing a bamboo salt product: taking out a bamboo salt rod and removing surface bamboo ash; and crushing to obtain the bamboo salt product. Potassium iodate is added into the bamboo salt product to prepare the iodine-added bamboo salt product. The re-crystallization preparation method has a simple process and is easy to control; the prepared product has the natural alkalinity and has abundant minerals and microelements; and the product is low in impurity content and stable in quality, and has good anti-oxidization and toxin expelling effects.