The paper explores the effects of converting negative appended reviews on online customers’ attitudinal ambivalence, which is one of the patterns of the emerging appended reviews forms. It is found through an experiment and ANOVA that reviews with a converting negative appended review affect online customers in a negative way to increase the attitudinal ambivalence, which is more powerful than ordinary negative reviews. And they also mitigate the biased assimilation caused by attitudinal ambivalence difference, and as a result the resistance to the negative reviews derived from positive attitude is impaired.