There is no doubt that Aphra Behn(1640-1689) should be placed as a representative female writer of the Restoration theatre. With women？ writing being regarded as a kind of prostitution by selling herself on the public arena during her time, Behn attained a new name？auth-whore？ which is frequently used by the critics to describe her. Throughout her oeuvre, prostitution stands out as a recurrent theme, emphasizing its similarity to marriage in the aspect that women are traded as a commodity in a patriarchal society where women are categorized according to the preservation of their virginity: virgin or whore. This binary conception of woman is questioned in Behn？ plays. The Feigned Courtesans in particular, by using the mask, represents two conceptions of women as either virgin or whore simultaneously in one body. Focusing on The Feigned Courtesans, this paper aims to explore how Behn provokes questions about gender ideology of women？ sexuality and identity and demolishes the binary conception of woman by using the courtesan？ mask. In the introduction, the overall importance of courtesans and prostitution and mask in Behn？ oeuvre is discussed. Part II ？earing the courtesan？ mask？examines the significance of three heroines？choice of feigning the courtesan. All of them, women of quality and high status, willingly decide to disguise themselves as courtesans. Interestingly, with their appearance as courtesans signifying their identity as courtesans, the courtesan？ mask leaves their real identity unquestioned, and enables the heroines to move beyond their limited space and enjoy their freedom. Part III ？aking off the courtesan？ mask？examines the inevitability of unmasking and its significance. To be included in their society, the heroines cannot help abandoning the courtesan？ masks and returning to their real identity. Besides, they should prove their virginity to achieve their love. The conclusion part considers the significance of Behn？ treatment of her heroines？ final return to their society. Behn had to negotiate with her society by returning them to the patriarchal society and thus relieving the dangerous transgression of the heroines？masquerade as courtesans. However, instead of being blamed for her limits, Behn deserves a positive evaluation. Within her limits Behn fully questioned the patriarchal ideology regarding women？ sexuality and binary positionality within the frame of the comedy on the Restoration stage.