[Aim]  To measure the functional response of Arma chinensis adults to different larval stages of Spodoptera exigua, and thereby assess the potential of using this species as a biological control for S. exigua. [Methods]  The ability of A. chinensis adults to prey on 1st, 2nd, 3rd, 4th and 5th, instar larvae of S. exigua was measured under laboratory conditions. [Results]  Predation dynamics for all instars were successfully modeled using a Holling type Ⅱ equation (R² =0.415-0.959). The predatory functional response of adults to 1st to 5th instar S. exigua larvae conformed to the Holling Ⅱ model. Compared to other larval instars, the predatory functional response of female adults to 1st, 3rd, and 5th instar S. exigua larvae best fitted the Holling Ⅱ model. The predatory functional responses of adult males to 1st, 2nd, 4th, and 5th instar larvae also best fit the model. The predatory capacity of adult male and female A. chinensis towards second instar larvae was the highest, with females consuming 27.777 and males 23.810, larvae. Adult females consistently showed higher predation rates than males. The instantaneous attack rates of female adults on 1st to 5th instar larvae were 0.201, 1.165, 1.101, 1.007, and 0.590, respectively, with handling times of 0.053, 0.036, 0.054, 0.128, and 0.151 d. The instantaneous attack rate of adult males was highest on third instar (1.595) and lowest for first instar (0.134) larvae. Handling times of adult males for 1st to 5th instar S. exigua larvae were 0.134, 0.042, 0.091, 0.072, and 0.113 d respectively. Search efficiency decreased as host density increased. [Conclusion]  Adult A. chinensis have strong predatory capacity for S. exigua larvae, particularly 2nd instar larvae. In addition, adult females have greater potential as biological control agents for S. exigua larvae than adult males.