Disclosed herein is a manufacturing method of plant root/stem fermentation substance having skin proliferation efficacy, comprising the following steps: (a) grinding roots/stems of rhizoma dioscoreae and mixing with water, whereby the soluble portion of the rhizoma dioscoreae aqueous mixture is formed into a rhizoma dioscoreae liquid (b) grafting the fermentation bacteria onto the rhizoma dioscoreae liquid, the fermentation bacteria can be selected from bacillus subtilis or lactic acid (c) subjecting the fermentation bacteria to a fermentation reaction for 18 to 84 hours in the mixture environment of rhizoma dioscoreae liquid and (d ) taking out the supernatant after fermentation. Experimental results confirm that this fermentation substance indeed has the proliferation effect of skin cells.
