[Objectives]  Using predatory mites to control plant leaf mites is standard biological-control practice and also an important method in pest ecosystem-control. We quantitatively analyzed the effect of 2 kinds of predatory mites, Neoseiulus californicus（McGregor）and Amblyseius orientalis（Ehara）on the abundance of plant leaf mites, including Panony chusulmi（Koch）and Tetranychus viennensis Zacher. [Methods]  The two predatory mites were released on apple trees from May to October 2019. [Results]  Both species of predatory mites adapted to the ecological environment of the orchard and easily controlled leaf mites; the control efficiency of N. californicus（McGregor）was 84.8%-100% and that of A. orientalis（Ehara）was 90%-100%. [Conclusion]  The 2 species of predatory mites are ideal biological control agents for leaf mites in apple orchards in Shandong province.