In Yi history, the Yi people have a unique understanding and knowledge of astronomy. The most famous application of their star-related knowledge is seen in their Ten-Month Solar Calendar and Yin-Yang Calendar. The Ten-Month Calendar divides the year into five seasons based on the Five Elements (Wood, Fire, Earth, Metal, and Water), with each season consisting of two months, totaling ten months. Each month has 36 days, with the final month having 35 days. The Eighteen-Month Calendar, on the other hand, divides the year into six seasons, with each season consisting of three months, and each month having 20 days. The remaining five days are reserved for a special holiday (either a sacrificial day or New Year's celebration).

Beyond the calendar, the Yi people also applied their knowledge of stars to agriculture. For example, when the Bison Star (Pleiades) appears on the eastern horizon at dawn, the Yi people take this as a sign of the arrival of spring and begin sowing seeds. Conversely, when the Bison Star appears on the western horizon at dawn, it signals the arrival of autumn, prompting the Yi farmers to begin harvesting. Another example is the Yi people's use of Sirius: when Sirius appears at dawn, it indicates the coming of the rainy season, while its appearance at dusk signals the arrival of the dry season.

Finally, there are the legends and beliefs about the stars. According to Yi mythology, the world initially existed in a state of primordial chaos, as described in the "Origin of the Yi": "In ancient times, when the sky was not yet formed, and the earth was not yet created, when there was no wind and no rain, there existed only clear and turbid energy." Later, the gods separated the chaos and created the world. The gods then placed stars in the sky, with each star representing the soul of a god or ancestor. These stars not only adorned the sky but also guided and protected the Yi people. In Yi legends, the Sun and Moon are a pair of siblings named Ali, who together govern the day and night. Their movement across the sky influences the seasons and the passage of time on Earth.