To evaluate the effects of external factors on the predation efficiency of Eocanthecona furcellata (Wolff) and improve its field biocontrol on Spodoptera litura (Fabricius) populations, a quadratic general rotation combination design was employed to examine the influence of three experimental factors on the predation efficiency of E. furcellata, including the density of S. litura larvae (X₁), the release quantity of E. furcellata nymphs (X₂), and the number of taro plants (X₃). Based on the predation rates of E. furcellata against S. litura under varing treatments, a regression model was established to describe the relationship between the predation efficiency (Y) and the three factors: Y = 71.8751593 - 4.74158206X₁ + 12.83546961X₂ + 1.249219611X₃ + 0.1022956216X₁² - 0.518515769X₂² - 1.076015769X₃² - 0.1667500000X₁X₂ - 0.0832500000X₁X₃ + 0.416250000X₂X₃. Single-factor effect analysis revealed the relative importance of the three experimental factors on predation rate in descending order as follows: the density of S. litura larvae (X₁), the release quantity of E. furcellata nymphs (X₂), and the number of taro plants (X₃). Through the fitting analysis of each factor when the highest index was taken in the established quadratic polynomial regression model and drawing of single-factor and interaction effects of the three factors, the optimal ratio for maximizing predation efficiency was determined to be 7∶5∶1.That was, the density of 7 S. litura larvae (X₁), the release quantity of 5 E. furcellata nymphs (X₂), and the number of 1 taro plant (X₃) could achieve a maximum predation rate of 90.83%.