清初政治動亂接連衝擊早已深陷朝廷改曆危機的欽天監世業疇人。康雍乾三朝重要數學家何國宗出身欽天監疇人世家，本文以其三代父祖在明末清初欽天監內的際遇為主題，探討何家成員如何在困境中採用不同方式，尋求個人職業進展，且為家族未來建立基礎。藉由重新審視何家成員在曆法爭議—主要是西洋新法與大統曆舊法—中的參與，本文闡明何家與康熙帝，在延續曆爭與其最後終止的一連串事件中，所扮演的角色。

Successive waves of political turbulence during the early Qing dynasty had a profound impact on the Chinese hereditary mathematician families of the Astronomical Bureau, who since the late Ming had been deeply involved in a crisis over calendar reform. This paper focuses on the important early Qing court mathematician He Guozong’s 何國宗ancestors, particularly his father’s generation and the two previous generations. Despite the difficult circumstances they faced in the Astronomical Bureau, the He family mathematicians sought to advance their careers in different ways, laying the foundations for the family’s future. This paper reinvestigates the He family mathematicians’ involvement in the dispute over calendar-making methods, in particular the New Western and Great Concordance methods, revealing the roles of the Kangxi Emperor and the He family in prolonging and finally ending the dispute.