Abstract: Objective This study aimed to evaluate the potential of Oenopia sauzeti in controlling and preventing Trialeurodes vaporariorum， thereby providing a theoretical basis for its use in managing this pest.Method Under laboratory conditions， the 2^nd-4^th instar nymphs and female adults of Oenopia sauzeti that had been starved for 24 h were placed with the 4^th instar nymphs of Trialeurodes vaporariorum at different density gradients in a circular insect box. The predation amount of the 4^th instar nymphs of Trialeurodes vaporariorum was recorded， and the predator functional response and searching efficiency of the 2^nd-4^th instar nymphs and female adults of Oenopia sauzeti on the 4^th instar nymphs of Trialeurodes vaporariorum were determined. The predation amount of female Oenopia sauzeti adults at different densities on 4^th instar nymphs of Trialeurodes vaporariorum at the same density was recorded to clarify the self-density interference of female Oenopia sauzeti adults. The predation amount of female Oenopia sauzeti adults on the 4^th instar nymphs and adults of Trialeurodes vaporariorum of different densities was recorded to clarify the predation preference of female Oenopia sauzeti adults.Result The functional response of the 2^nd-4^th instar nymphs and female adults of Oenopia sauzeti to the 4^th instar nymph of Trialeurodes vaporariorum fit the HollingⅡdisc equation model. The instantaneous attack rates of the 2^nd-4^th instar nymphs and female adults of Oenopia sauzeti to the 4^th instar nymphs of Trialeurodes vaporariorum were 1.008， 0.996， 1.234 and 1.187， and their handling durations were 0.030， 0.012， 0.009 and 0.008 d respectively. The predation capacity of the female Oenopia sauzeti adults to the 4^th instar nymphs of Trialeurodes vaporariorum was the highest （148.363）， followed by the 4^th instar nymphs （134.109）， the 3^rd instar nymphs （81.630） and 2^nd instar nymphs （33.378）. The searching efficiency of the 2^nd-4^th instar nymphs and female adults of Oenopia sauzeti on the 4^th instar nymphs of Trialeurodes vaporariorum decreased with increasing prey density. Under the conditions of fixed density of the 4^th instar nymphs of Trialeurodes vaporariorum， the predation rate of Oenopia sauzeti decreased as its self-density increased， and the interference equation was E=1.448P^-0.116. When both the 4^th instar nymphs and the adults of Trialeurodes vaporariorum coexisted， the female Oenopia sauzeti adults showed a predation preference for the 4^th instar nymphs of Trialeurodes vaporariorum.Conclusion Oenopia sauzeti shows a predation preference and significant control potential against the 4^th instar nymphs of Trialeurodes vaporariorum.