The biodiversity of insects visiting cabbage and population dynamics of diamondback moth was studies on Golden acre variety of cabbage. The experiment was conducted at experimental plot of Ramakrishna Mission Vivekananda Educational and Research Institute, Morabadi, Ranchi, during October to January, 2018-19. During the experiment, Bihar hairy caterpillar, Diamondback moth, Cabbage aphid, Cabbage maggot, Cabbage butterfly, Tobacco caterpillar, Ladybird beetle, Rice bug, Cricket and Spider were noticed. The population of diamondback moth was positively correlated with maximum, minimum, average temperature and maximum relative humidity and negatively correlated with minimum RH, wind speed; rainfall. The highest larval population of was recorded during 1st week of January (1st Standard Meteorological Week, SMW).