From the perspective of corporate rumors and clarification announcements，this paper investigates the problem of short-selling and informed trading in a sample of Chinese A-share listed companies between April 2010 and March 2018. The empirical results show that，first of all，the pre-rumor abnormal short-selling is significantly negatively correlated with the post-rumor stock return，indicating that short sellers can predict the release time and content of corporate rumors in advance and therefore are informed traders. Secondly，effective clarification announcements can moderate the negative relation between pre-rumor short-selling and post-rumor stock return，indicating that short sellers can anticipate the effectiveness of clarification announcements to some extent，which further supports the conclusion that“short sellers are informed traders”. Further study shows that short sellers can distinguish whether the rumors are true or false，and that private information mining is an important source of short sellers’information. Based on the practice of short selling in China， this paper provides new empirical evidence for the debate whether short sellers are informed traders，and has important practical significance for the perfection of short selling mechanism，the countermeasure of corporate rumors and the regulation of media.