This study aims to explore the reasons for the popularity of a specific collection of Tang poems and introduce a new quantitative research direction for Tang poetry. Our approach includes two procedures. We first use factor analysis to analyze the data provided in the book "Ranking of Tang Poems", which is followed by interpreting the extracted factors based on literary theory regarding the popularity of Tang poetry. Then we use word embedding techniques to further justify the suitability of the results extracted by factor analysis. After deciding a two factor solution to the factor analysis, we interpret the two factors that may explain the popularity of Tang poetry to be "history related strength" and "poetic classicism". A poem with high "history related strength" makes references to well-known historical events. "Poetic classicism" indicates that the poem can be considered as a classic to a certain literary school of thoughts from the academic perspective. Using word embedding techniques to study the textual similarity among poems, we find that each factor has a significant or highly significant rank correlation with the textual similarity, which is based on the top five ranking poems of the corresponding factor.