Abstract: 【Objective】The present study aimed to clarify the biological control potential of Eocanthecona furcellata against Helicoverpa armigera larvae,and to provide research references for the biological control of Helicoverpa armigera.【Method】The predation functional response of 4^th and 5^th instar nymphs and female adults of Eocanthecona furcellata was evaluated against 2^nd and 3^rd instar larvae of Helicoverpa armigera,and the search effect and predation efficiency were assessed.The intraspecific interference effect of 5^th instar nymphs and female adults of Eocanthecona furcellata on 2^nd instar larvae of Helicoverpa armigera was studied using the interference effect model.【Result】The results showed that both the 4^th and 5^th instar nymphs and female adults of Eocanthecona furcellata preyed on the 2^nd and 3^rd instar larvae of Helicoverpa armigera.The amount of predation increased gradually with the increase of prey density,but the increase rate decreased gradually with the increase of Helicoverpa armigera larvae density.At the same time,with the increase of the age of prey,the predation number by Eocanthecona furcellata decreased gradually at the same developmental stage.The maximum predation amounts of the 4^th and 5^th instar nymphs and female adults of Eocanthecona furcellata on the 2^nd instar larvae of Helicoverpa armigera were calculated as 32.776,39.756 and 47.064 individuals per day.Among them,the female adults of Eocanthecona furcellata had the highest pest control efficiency （40.748） against the 2^nd instar Helicoverpa armigera,with the highest instantaneous attack rate （0.866） and the shortest prey handling time （0.021 d）.With the increase of the density of Helicoverpa armigera,the search effect of Eocanthecona furcellata on Helicoverpa armigera larvae decreased.Under the same prey density,the searching efficiency of Eocanthecona furcellata was as follows:female adult＞5^th instar nymphs＞4^th instar nymphs.There were no significant differences in the search duration and successful sucking duration of the 4^th and 5^th instar nymphs and the female adults of Eocanthecona furcellata on the 2^nd instar larvae of Helicoverpa armigera （P＞0.05）,but the sucking duration of female adults was significantly longer than that of the 4^th and 5^th instar nymphs （P＜0.05）.At the same time,the predation of Eocanthecona furcellata was affected by interference of its own density.The average predation amount and predation rate of 5^th instar nymphs and female adults on the 2^nd instar larvae of Helicoverpa armigera decreased gradually with the increase of population density.The intraspecific interference effect of female adult Eocanthecona furcellata was greater than that of 5^th instar nymphs,and the maximum competition intensity of female adult was 0.731,that of the 5^th instar nymphs were 0.687.【Conclusion】Eocanthecona furcellata has strong control ability against Helicoverpa armigera,with the female adults having the strongest control ability against2^nd instar Helicoverpa armigera larvae.When using Eocanthecona furcellata to control Helicoverpa armigera in the field,it should be carried out before the 2^nd instar of Helicoverpa armigera larvae,so as to fully utilize the predatory and pest control abilities of natural enemies.