In this paper, I analyzed the records of solar and lunar eclipses in the four books, namely, the Book of Song 宋書, the Book of Southern Qi 南齊書, the Book of Wei 魏書, and the Book of Sui 隋書 among the official Twenty-Four Histories of Imperial China. In these books, the Chinese have officially recorded the astronomical phenomena in the Southern and Northern Dynasties. As a result, I came to know the following facts. Firstly, astronomical records were religiously kept in both the Southern and Northern Dynasties. The Chinese have tried to maintain records of astronomical phenomena without fail since Sima Qian wrote the Records of the Grand Historian 史記. Secondly, there were differences between the astronomical records of the Southern and Northern Dynasties. For example, the Northern Dynasties recorded the solar eclipses more carefully and more frequently than the Southern Dynasties did. Thirdly, the portent theory, which is a basic viewpoint in understanding natural phenomenon in ancient China, still remained strongly in the Northern Dynasties. We could see that the portent theory was applied differently in the two dynasties even during the same era. Lastly, it has become important for the Chinese to record lunar eclipses from the late 5th century. At that time lunar eclipses started to become portent phenomena.