[Aim]  The aim of this study is to investigate the interspecific interactions between the predator Nesidiocoris tenuis and the parasitoid Encarsia formosa, with the goal to optimize the combined use of these two natural enemies in controlling the whitefly Bemisia tabaci. [Methods]  Through different release methods of natural enemies and two host density experimental design, tests were conducted to quantify the predation and preference of N. tenuis on unparasitized whitefly nymphs and parasitized whitefly nymphs at different developmental stages. Experimental populations were then observed to evaluate the effects of predation on the parasitism rate and control efficacy of E. formosa. [Results]  Compared with unparasitized whitefly nymphs, N. tenuis displayed a preference for predating parasitized whitefly nymphs when the parasitoids inside the hosts were at the egg and larval stages. However, the predation rate decreased significantly from 85% to 11% once the parasitoids reached the pupal stage. When comparing the two whitefly population densities, the parasitism rate and control efficacy of E. formosa was not significantly affected by N. tenuis when E. formosa and N. tenuis were released simultaneously or when E. formosa was released 10 d in advance. However, there was a significant decrease in the parasitism rate and control efficacy of E. formosa when E. formosa was released only 3 d before N. tenuis. [Conclusion]  The predation of N. tenuis on  E. formosa varies depending on the developmental stage of the parasitoid. When attempting to use E. formosa and N. tenuis in combination for whitefly control, it should be avoided the release of N. tenuis 3 d after E. formosa, to reduce the predation of N. tenuis on E. formosa, and in turn enhance their joint control efficacy on the whitefly.