【Aim】 To examine the predatory capacity of Arma chinensis on Henosepilachna vigintioctopunctata. 【Method】 We measured the predatory function response and searching efficiency of the 5th instar nymphs of A. chinensis to the 2nd and 4th instar larvae of the H. vigintioctopunctata. 【Result】 Our results demonstrated that the predatory function responses of the 5th instar nymphs of A. chinensis to the 2nd and 4th instar larvae of H. vigintioctopunctata conformed to the type Ⅱ functional response. When the density of H. vigintioctopunctata increased, the searching efficiency of A. chinensis gradually decreased. In addition, the searching efficiency of the 5th instar nymphs for the 2nd instar larvae was significantly higher than that for the 4th instar larvae. The maximum numbers of 2nd and 4th instar larvae of H. vigintioctopunctata predated by the 5th instar nymphs were 15 and 10, respectively. 【Conclusion】 In summary, our data indicated that A. chinensis has a beneficial predation effect on H. vigintioctopunctata.