Counter-rumor is an important means to eliminate the influence of online rumors. But it is not always effective to refute rumors, and in some cases backfire effect even appears. Raising the credibility of counter-rumor is very important, but there is still a lack of discussion on the mechanism that affects the credibility of counter-rumor. This paper establishes a credibility model of counter-rumor from the perspective of information audience perception, which is verified by two empirical researches. The result is that information quality, source credibility and original attitude are the main factors affecting the credibility of counter-rumor. In addition, information involvement plays a moderating role. For high-level involvement users, quality of information and the credibility of information sources have significantly effect and original attitude has little effect. For low-level involvement users, the information quality has little effect, the original attitude and credibility of information sources have significantly effect.