《睡虎地秦簡》於1975年出土，其中《日書．玄戈》篇內容包含月份、十二地支、星宿還有吉凶等占文。然而，簡文與天文現象間的關聯深奧難懂，篇中星宿是否為真實天象也曾有爭論。本文以天文學的角度，修正簡文內容，試圖理解占文規則，並以天象模擬軟體，驗證出簡文中的月份與星宿、每季首日星宿記錄等，皆為當時的天象。接著分析「玄戈擊」與「招搖擊」，解釋文章中的「擊」，意為「對衝」，且「玄戈擊」的指向均屬「致死」，說明簡文的吉凶判斷規則。最後討論「左旋」、「右旋」的意涵，嘗試解釋「地右動」的思想根源，很可能來自古人對歲星的觀測。〈玄戈〉篇內容包含天文與數術，可為星占到堪輿的歷史發展依據，值得更深入解析。

The Shuihudi Qin bamboo slips were excavated in 1975 at ShuiHudi in Hubei, China. Among the texts from the bamboo slips, the chapter of “Xuange” in Rishu (the Day Book) includes divination manuals and practices based on months, the twelve Earthly Branches, constellations, and good and ill omens. However, the relationship between the bamboo slips and observational astronomy is difficult to trace. For instance, it is open to debate whether the names mentioned correspond to real celestial objects or are simply symbolic representations. As such, this article aims to reassess the information from the bamboo slips and tries to understand the rules of divination from an astronomical perspective. By applying planetarium simulation softwares, this paper provides examples of correlation between bamboo slip records and stellar constellations for each month of the year, as well as visible stars in the first evening of every season, as an attempt to prove that the records were documented based on actual astronomical observations. Next, the article analyzes the meaning of “Xuange hit” and “Shaoyao hit,” and suggests that the “hit” entails the idea of “opposition and the principles of good and ill omens.” Finally, the article discusses the rightward and leftward movements of deities across the sky, and argues that the concept of the Earth's “rightward movement” might be derived from the observations of the orbit of Jupiter (the Year Star). As the chapter of “Xuange” includes the studies of astrology and divination, its informative contents further constitute the later development of geomancy (Kanyu); hence, to fully understand these issues, the Shuihudi Qin bamboo texts deserve further research considerations.