Abstract: The ancient Greek riddle of the Sphinx underwrites an intertextual perspective on the White Snake in Fang Chengpei's The Legend Leifeng Tower and the Mermaid in Hans Christian Andersen's Little Mermaid, both of which are generally seen as classic and symbiotic female images and metaphors of human desires, life purport, and ethical paradoxes. Viewed in the light of ethical literary criticism, the two protagonists' pursuit of human forms and human nature can be interpreted as their efforts to make a balance and a choice between animal factor and human factor. In the name of metamorphosis and love, the two female protagonists try to solve their own riddles of the Sphinx by sacrificing their magic power and sweet voice respectively. Though their efforts in vein, their suppression of natural will and pursuit of human benevolence is much adored and is suggestive of human beings' ultimate pursuit of goodness.

Key words: White Snake, Mermaid, the Sphinxiddle, ethical chaos, ethical selection