Abstract: The predatory mite, Neoseiulus californicus (McGregor), was recently recorded in China. The previous experiment showed that N. californicusis had high consumption rate and high fecundity when feeding on spider mites. Preference in N. californicus for prey stages of spider mite Tetranychus cinnabarinus was studied in laboratory at 25 ℃, RH (80±5)%, and a 16L:8D photoperiod. Functional responses of N. californicus and Amblyseius pseudolongispinosus to the spider mites were also measured. N. californicus preferred nymph to larva of the spider mite, egg was the least preferred stage. When prey density was more than 20 eggs or 15 nymphs, N. californicus preyed significantly more than A. pseudolongispinosus did. Functional responses of the two predatory species on each prey stage (egg, larva or nymph) could be described by the HollingⅡ type. Suppression (a'/T_h) of the three prey stages was greater by N. californicus than by A. pseudolongispinosus. When eggs or nymphs of T. cinnabarinus were used as prey, the daily maximum theoretic number of consumed prey in N. californicus was 35.0% or 37.1% more than that in A. pseudolongispinosus, but 8.0% lower when larvae of spider mites were supplied. The results suggest that N. californicus may be a potential biological control agent against the spider mite.