[Aim]  To determine if the predatory mite, Cheyletus eruditus, has the potential to act as a biological control for grain storage pests in China. [Methods]  In this study, the predation function of each mite state of common carnivorous mites to different developmental stages of Cryptolestes turcicus was systematically measured through 12 replicates of feeder control experiments under gradient temperature and humidity conditions, and the predation volume-mortality data were analyzed. [Results]  The predatory functional response of the 3 developmental stages of C. eruditus to C. turcicus, can be ranked as follows: Adult females > deutonymphs > protonymphs. The functional response of adult females to 1st instar larvae was higher than that to second-instar larvae, or eggs. The functional response of adult females to 1st instar larvae was of the Holling type Ⅱwithin a temperature range of 16-28 ℃ and 75% RH, and at 28 ℃ at a RH of 57%-93%. The functional response of adult females to 1st instar larvae was positively correlated with temperature. Although the functional response of adult females to 1st instar larvae was highest at 75% RH, it was not correlated with humidity at a temperature of 28 ℃ and RH values of 57%-93%. [Conclusion]  Based on research using the HollingⅡfunctional response model, the predation efficiency of different stages of the predatory mite C. eruditus on different developmental stages of C. turcicus exhibits a density - dependent positive correlation. Female adult mite show a significant predation advantage on the eggs of C. turcicus, indicating its potential for biological control against stored-grain pests and applicability in ecological regulation of resistant fumigation populations.