Exploring the variables affecting its communication effect can serve a valuable function to increase the knowledge of in what way social media can be better applied in archival enterprise. By means of the WeChat Communication Index（WCI）offered by Qingbo Data Platform, this paper attempts to investigate factors affecting the communication effect of archives WeChat official account from four dimensions: content, subject, the relevance of social hot spots and push strategy. Regression analysis based on 289 archives Official Account indicates that content plays the most important role in drawing public attention. The official account tends to receive more positive public attention when articles posted in it are original and archives-related. In addition, the communication effect is likely to be improved when the push frequency is higher, but the subject and the relevance of social hot spots are irrelevant. For archivists, the“old”truth for employing the“new”media is returning to the archive itself and voicing to the public continuously.