Abstract  [Aim]  To better understand the effect of host plants and Spodoptera exigua on the tendency behavior of Microplitis pallidipes. [Methods]  Maize and amaranth were chosen and the behavioral responses of M. pallidipes to normal plants and larva-plant complex were determined with Y-tube olfactometer, and the volatile compounds were analyzed and identified by GC-MS. [Results]  The normal maize and amaranth had no attraction effect on M. pallidipes, but larva-maize complex and larva-amaranth complex exhibited significant attractiveness, and larva-maize complex showed stronger activity than larva-amaranth complex. GC-MS indicated that 22 compounds were detected in normal maize leaves with alkanes and aromatic hydrocarbons as the main constitutes, while 31 compounds were identified in the larva-maize complex and mainly alkanes and alcohols. Similarly, there were 16 compounds in normal amaranth and the content of alkane compounds was the highest with 54.75%. The larva-amaranth complex contained 55 compounds, and alkanes, aromatics, alkenes, acids and aldehydes were relatively high. In addition, some compounds were only produced or increased remarkably in larva-plant complex, such as 2-hexenal, (+) -limonene, α-caryophyllene, DMNT, and α-himachalene. [Conclusion]  M. pallidipes were prefer the larva-maize complex, and a wider variety of compounds were released by maize and amaranth after feeding by Spodoptera exigua.