Abstract: To bring the pest control activity of predacious natural enemies into good play on cotton, a series of field investigations and indoor tests were carried out for getting their population dynamics along with the development of cotton in eight different cotton agroecosystems, and the energy currency parameters of the populations of predacious ladybirds, bugs, spiders and whole predators were calculated according to a unified energy unit. The characteristics of energy intake and exploitation of each predacious natural enemy population in different types of cotton fields with different sowing times, intercropping and tillage systems were analysed and compared with each other. The dynamic regularities of pest control activities and the functions and locations of different predacious natural enemies in different cotton agroecosystems were summarized and evaluated.

Key words: predacious natural enemies, population energy dynamics, predatory activity