[Objectives]  Lagopsis supine has high medicinal value, a long flowering period and a wide distribution in northern, northeast, southwest and northwest China. In orchards, L. supine can increase the control exerted by natural enemy insects on target pests. However, the specific mechanism responsible for this effect has not yet been clarified. We investigated the effect of L. supine flowers on the survival time and predatory (or parasitic) ability of natural enemy insects to see if this might explain the ecological effect of this plant. [Methods]  We selected Orius sauteri and Trichogramma dendrolimi, a predatory and parasitic insect, respectively, both of which are common in orchard ecosystems. The treatment groups were either 5 or 20 L. supine flowers and flowers without the two study species were the control group. The lifespan and predation (or parasitic) ability of the two natural enemy insects were quantitatively assessed in the laboratory. [Results]  Compared with the control, the 20-flower treatment significantly prolonged the lifespan of O. sauteri, (t=2.79, df=66.063, P=0.001) and significantly (F_2,14=5.14, P=0.024) increased the number of eggs laid by this species. However, there was no significant effect on predation ability (t=1.28, df=5.554, P=0.155). With respect to T. dendrolimi, both the five and 20 flower treatments, significantly prolonged the lifespan of this parasitic wasp (t=2.31, df=68.052, P=0.014; t=4.09, df=57.667, P=0.006). In addition, the parasitic ability of T. dendrolimi was significantly higher (F_2,14=4.69, P=0.03) in the 20-flower treatment group, with an average parasitism rate of 63.33 eggs per female. [Conclusion]  L. supine in orchards conserves natural enemy insects and enhances the control they exert on pests. The underlying mechanism appears to be the prolongation of the lifespan of predatory and parasitic insects, thereby increasing the duration of predation or parasitism. L. supine may also improve egg production or parasitic ability.