[Aim]  To evaluate the effect of diapause in Aphidoletes aphidimyza on the ability of larvae to prey on Megoura crassicauda. [Methods]  Third instar larvae were randomly assigned to either a diapause termination, or non-diapause treatment, groups, after which their functional response, search efficiency, intraspecific interference, and predation preferences were systematically investigated under laboratory conditions. Larvae were starved for 12 h before being exposed to different instars of M. crassicauda. [Results]  The daily predation rate of 3rd instar larvae after diapause termination was slightly higher than that of the non-diapause group, but this difference was not significant (P = 0.730). The predation functional response of both treatment groups on M. crassicauda fitted the Holling TypeⅡmodel, and both exhibited the strongest predation on 1st and 2nd instar nymphs of M. crassicauda. As the density of M. crassicauda increased, the search efficiency of 3rd instar larvae after diapause termination was slightly higher than that of non-diapause larvae, but this difference was not significant (1st and 2nd instar: P = 0.577; 3rd instar: P = 0.665; 4th instar: P = 0.678). Furthermore, the predation rate of larvae decreased with increasing density. The predation rate of the diapause termination group was slightly higher than that of the non-diapause group, but this difference was not significant. Diapause did not alter the prey preferences of larvae towards M. crassicauda, larvae from both treatment groups preferred to prey on 1st and 2nd instar nymphs with respective preference coefficients (Q) of 1.35 and 1.39. [Conclusion]  Diapause somewhat enhanced the predatory capacity of A. aphidimyza larvae with respect to M. crassicauda, indicating that post-diapause larvae may be more effective predators of M. crassicauda. This study not only provides an important theoretical basis for using A. aphidimyza as biological control, but also lays a foundation for further exploration of its diapause mechanism.