Abstract: Purpose/Significance Review dimension refers to the number of product attribute dimensions involved in an online review. The more the review dimension is, the more comprehensive the review is. Review dimension conveys the multi-dimensional information of a product, which saliently affects consumers' purchase decisions. But there is little study on the causes of review dimension. Design/Methodology In this paper, 248,881 pieces of review data on Tmall platform were analyzed, and the influence of two review content characteristics, review length and sentimental strength, and product type on review dimension was demonstrated. A regression model was conducted. Findings/Conclusions The results indicate that consumers of experience products tend to deliver more information than consumers of search products. The results also reveal that review length and sentimental strength have positive impacts on the review dimension, and product type has a significant moderation effect upon the relationships. Six methods were used to confirm the reliability of the above conclusions. The findings not only enrich the researches on review dimension, but offer suggestions for e-commerce platforms and online retailers to effectively manage online reviews.