Abstract: Online rumor is a social phenomenon with the Internet serving as its chief media and platform. Compared to the more traditional rumor which runs from mouth to mouth， online rumor， which exists on the virtual network platform， manifests itself in dual hermeneutics properties which raise a core issue—the interpretation of online rumor. Meanwhile， rumormongers familiarity with and good use of the netizens prejudice and the objective time space between the netizens and online rumor texts serve as the core elements and basic conditions for the netizens to deeply interpret online rumor. Therefore， the realistic difficulties caused by online rumor are regarded as an interpretation dilemma， to which three possible solutions might be found. To construct a harmonious， healthy and democratic network environment， it is suggested that online rumor texts should be tackled directly， the netizens prejudice should be dissolved and the supervision from the others should be reinforced in the process of rumor formation and diffusion.

Key words: online rumor, prejudice, time space, interpretation dilemma