The part one in Quli in the Records of Rites notes that the odd days used for external affairs, and the even ones used for internal affairs. Ye Guoliang verifies that internal affairs recorded in the Spring and Autumn Annals Jingzhuan and ancestor worship used even days often. This study is based on the Spring and Autumn Annals Jingzhuan to clarify the related records and divide the affairs which possibly used the even days into two categories— ancestor worship and politics. Even days are used 100% chance in ancestor-worshipping affairs, such as telling deities of holding mourning ceremony, rural festival, or praying for rain. Political affairs includes new emperor ascending the throne and worshiping at the ancestral shrine, which can be calculated together and the even days they used is 63.64%, the alliance between the emperor and officials or officials and officials, which is calculated as 72.73%, and the emperor and officials absconding to other countries, which is calculated as 82.35%. This study probes into the reasons why political affairs mentioned above used even days often. This research can not only make sure the saying that internal affairs used even days, but also know that using even days was related to sacrifices.