中國古代曆日的發行量相當大，並為中國社會居家必備的書籍。其內容並不僅僅在藉紀日以表示日月運行的規律，而王要在希冀能透過鋪註，以掌握行事的宜忌。明末以來，入華的天主教士或受當代歐洲人知識經驗以及教會態度的影響，多在強烈的文化優越感下，對擇日之說採取拒斥或批判的態度。在掌理監務之初，湯若望雖希望能在曆日中改依實用新法鋪註，然其主張並未獲清政府採行。但湯若望仍利用職權，對舊曆的內容做了有限度的改革。惟在強大傳統的壓力之下，這些變革並未能刪改去民層中鋪註選擇的內容，同時，它們亦不為精確推步天象時所必需。湯若望在民曆中改行這些新法的目的，很可能主要是希望造成一種西法符合天行的整體印象，藉以打壓中法。
由於此等興革與傳統的知識經驗相差頗大，且令術家陰陽生剋的理論基礎發生嚴重混淆，故引起中國社會極大反彈。而在另一方面，湯若望或為求穩固其在監中的地位，故對舊曆中的選擇術亦不曾進行全面性的批判，此一態度也引起部份教內人士的嚴辭抨擊，在經過長達十多年的激烈爭辯後，教會當局終於康熙三年裁決曆日中的陰陽選擇術為不合乎教義的迷信內容。但湯若望尚未及對此一衝擊有所調適，即在中國保守人士楊光先等對其所編曆日及其所用擇日術的抨擊之下，由位居極品而驟然鋃鐺入獄，並於不久後謝世。
湯若望一生中較重要的事件，幾乎均環繞在曆日四周。由於工作性質的影響，湯若望個人很不幸地屢屢處於中西文化的夾縫之中，本文透過對新、舊曆日內容異同的分析，呈顯出湯若望在清初中西兩文化接觸時所扮演的尷尬角色，而其所編之曆日，更成為此兩大文化衝突與妥協後的最具體例證。

　　　　　Being an indispensable reference book for daily-life activities, millions of civil calendars were issued every year in ancient China. Apart from setting the beginning date as well as length of each month and year, traditional Chinese calendars were aimed at providing people with advice about what to do and what not to do. From Late Ming onward, some Jesuit missionaries entered China for preaching Christianity. Probably affected by the European learning as well as the Church's view, the missionaries,' in general, bore hostility against the occult sciences involved in Chinese calendars.
After the Manchus assumed the reins of government, Schall took over the Imperial Astronomical Bureau. He had proposed to make sweeping changes in the traditional calendars by Western methods; this idea, however, was not favored by the government. Nonetheless, certain innovations, later on, were imposed on the civil calendars.
In part because these reforms were contradictory with the traditional experience, and in part because they did not conform to the rationale of yinyang and wuhsing, Schall's new calendars incurred great repercussion from the Chinese society. While on the other hand, maybe for consolidating his position in the Bureau, Schall inclined to hold a more tolerant attitude toward the divine expressions applied in traditional civil calendars. Practical as the attitude might be, it had no way to get the overall approval of the missionaries, and caused Schall to be severely reproached. It followed that controversies about the divine expressions arose among the Jesuit missionaries. In 1664, the Church finally concluded that what concerned with occult sciences in Chinese calendars should be subsumed under superstitions.
Before giving any response to this conclusion, Schall was charged by Yang Kuang-hsien and the other Chinese conservatives; this accusation was well known as K'ang-hsi Calendar Lawsuit. Consequently, Schall was put in jail, and not long afterwards, he passed away.
Throughout Schall's life, what influenced him most were on the whole focused on the calendrical issues. Owing to his duty in the Bureau, Schall was often placed in the dilemma derived from the discrepancies between the Eastern and Western cultures. Through analyzing the contemporary calendars, both old and new, this paper showed that the civil calendars compiled by Schall bore witness to the confrontation and compromise of these two cultures in Early Ch'lng.