Abstract: As a commercially produced natural enemy species, Neoseiulus barkeri is often mass reared using the Tyrophagus putrescentiae. To investigate the impact of prey diet nutrients on N. barkeri, T. putrescentiae was reared on wheat bran diet (named as TPA) and wheat bran plus yeast diet (as TPB). Female body sizes and functional responses for Tetranychus cinnabarinus larva and Frankliniella occidentalis nymph of N. barkeri reared on TPA and TPB were compared at (25±1) ℃, 80% RH, and a 16L﹕8D photoperiod. Results showed that added yeast in prey diet had little influence on the body size of N. barkeri. The dorsal shield length and width of N. barkeri were about 368 μm, 200 μm, respectively. Functional responses of N. barkeri on F. occidentalis and T. cinnabarinus fit Holling typeⅡ equation. With yeast added, suppression (a'/T_h) of T. cinnabarinus larva and F. occidentalis nymph by N. barkeri increased significantly from 262.537, 9.731 to 279.726, 12.483 and the theoretic daily maximum consumption rate increased by 2.48%, 7.22%, respectively.