[Objectives]  To clarify the parasitic behavior of Eretmocerus gunturiensis, a newly discovered natural enemy of Aleurocanthus spiuiferus in Shandong tea plantations, and provide data to support the research and development of new, environmentally-friendly control methods for tea pests. [Methods]  The population dynamics of E. gunturiensis were recorded using the sweep net and yellow sticky-board methods. The morphological characteristics of E. gunturiensis were observed using an ultra-depth of field electron microscope and the size of A. spiuiferus pseudopupae after parasitism, were measured. The parasitism of E. gunturiensis on A. spiuiferus was investigated using the canopy sampling method. [Results]  E. gunturiensis larvae parasitize 2nd to 3rd instar nymphs of A. spiniferus. The laying time of female adults lasts about 2 minutes, and the eggs are laid between the abdomen of A. spiniferus and the leaves. E. gunturiensis bites the shell at the posterior of the pseudopupa of A. spiniferus with its mouthparts during emergence, and resultant hole is round but irregular. Parasitism by E. gunturiensis affects the size of A. spiniferus pseudopupae. The length and width of parasitized pseudopupae were significantly shorter than those of the non-parasitized pseudopupae. The parasitism rate of E. gunturiensis was significantly higher on leaves in the middle of a tea bush than in the upper and lower bush. [Conclusion]  E. gunturiensis is a newly discovered natural enemy of A. spiniferus in Shandong tea plantations and has the potential to be a useful biological control for this pest.