Abstract: The morphological and biological characteristics of Euagoras plagiatus were studied through the indoor rearing, which provided basic data for the study of using this natural enemy to control insect pests. Under the artificial environment of temperature being (26±1)℃, light being 16L∶8D and relative humidity being (65±5)%, Tenebrio molitor was used to feed E.plagiatus. The biological characteristics of E.plagiatus, such as the morphological characteristics of eggs, nymphs and adults, the developmental duration, predation, and fecundity were observed and recorded, and the generation duration and effective accumulated temperature were analyzed. The results showed that: under the laboratory conditions, the egg stage of E.plagiatus was (8.50±0.74) days, and there were five instars in the nymph stage. The pre-oviposition period of the adult was (14.80±3.71) days. The average number of eggs laid per female was 216.80±106.04, and the average life span of adults was (147.35±72.36) days. The average duration of one generation under the laboratory conditions was 81.38 days, and the effective accumulated temperature was 2115.88 days·degree. E.plagialus could prey on Spodoptera frugiperda, Argyrogramma agnata, Spodoptera litura, Brachmia macroscopa, Plutella xylostella, Pieris rapae, Cryptolestes turcicus, and Culex quinquefasciatus. The study showed that E.plagiatus occurred four generations a year in the laboratory environment and could prey on a variety of pests, which could provide an important reference for the further protection and utilization of this natural enemy.