Algorithmic distribution has become the main distribution mode of online news. And Weibo “Hot Search” is a typical application of the algorithmic distribution mode in social media platforms. This article, from the perspective of Critical Algorithm Studies, seeks to investigate the gatekeeping criteria of Weibo “Hot Search”. Based on the analysis of Weibo’s annual reports, press releases, patents, offcial statements as well as 2400 pieces of “Hottest Searches”, this study identifes a set of four algorithmic values: instantaneousness, popularity, user engagement, and correct orientation, which are embedded in the code writing and design. Therefore, Weibo’s values, assumptions, and biases are moved “upstream”. In order to construct the discursive legitimization of algorithmic gatekeeping, Weibo uses a series of tactics to present the generation of “Hot Search” as natural and inevitable, including the realtime update of the search index, the indication of “people are searching” in the search box, and the rhetorics of “presentations” and “re?ections”.