[Objectives]  To investigate predation by Andrallus spinidens on 3rd instar Spodoptera frugiperda larvae and thereby determine the potential of using A. spinidens as a biological control for S. frugiperda. [Methods]  Third instar S. frugiperda larvae were randomly assigned to different density treatment groups in the laboratory and the number of larvae consumed by 3rd to 5th instar A. spinidens nymphs and adults was measured and compared. The functional response, search effect and the interference effect of A. spinidens density were also estimated. [Results]  Under the set conditions, the daily average predation of A. spinidens at different instars showed an overall increasing trend with the increase of prey density, and the predation amount of 5th instar nymphs was the largest, and the predation functional response of A. spinidens at different instars showed a Holling II functional response. The functional response parameters showed that the predatory ability of the 5th instar nymphs was the strongest, and the predatory ability of the male adults was the weakest, with ɑ/T_h values of 41.241 and 14.519, respectively. The handling time of the 4th instar nymphs was 0.010 d, which was obviously shorter than that of other instars. With the increase of prey density, the search efficiency of decreased in general, and intraspecific interference was positively correlated with the density of A. spinidens. [Conclusion]  The 5th instar nymphs and adults (female) of A. spinidens have large food intake and strong predation ability, and can be used as alternative natural enemies to effectively control outbreaks of S. frugiperda.