Antarctic krill () is one of the largest single species of biological resource on the planet. It lives mostly in the waters south of 50° S in the Southern Ocean, and is distributed around the Antarctic. Studying the behavior patterns of Antarctic krill clusters is of great significance for understanding their distribution characteristics, the formation mechanism of Antarctic krill fishing grounds, and resource utilization. As Antarctic krill occupies a key position in Antarctica and the Southern Ocean ecosystem, the regionality of its living conditions, special rhythms, and vulnerability, have made it difficult to study the rules governing its aggregation. Antarctic krill uses the phenomenon of diel vertical migration and aggregation. In this study, diel aggregation and Antarctic krill biology were studied in the waters of the South Orkney Islands. The results show that the horizontal band which refers to the pattern of aggregation has a dominant distribution in each time period, but that the proportion of horizontal band in each time period is significantly different. From dawn to dusk, the proportion of the horizontal band decreased first, and then increased, reaching the lowest value in the daytime period (65%). From dusk to morning twilight, the proportion of the horizontal band was high and stable. Spherical distribution maintains a relatively stable time interval, and scattered distribution is a continuous feature from sunrise to the daytime. The central depth of the Antarctic krill aggregation varies greatly during different time periods; morning twilight and evening twilight are the dividing points of the average aggregation center depth. The central depth of Antarctic krill is also different in terms of aggregation. The average central depth of the spherical distribution is the largest, followed by scattered distribution. Alternately, the average central depth of the horizontal band is the least. The temperature of aggregation fluctuates in different time periods, ranging from -1.6℃ to 1.3℃. The minimum value appears during the evening twilight period, and the maximum value appears at night. The temperature of aggregation and the central depth of the Antarctic krill show a significant negative correlation. The body length of Antarctic krill is significantly different in different time periods (<0.001), and the dominant body length in different time periods is significantly different, with the dominant body length between daytime and afternoon being significantly higher than in other time periods.