Biological control of twospotted spider mite, Tetranychus urticae by releasing Amblyseius womersleyi was applied in a protected pear orchard. A. womersleyi was released into a plastic house pear orchard to determine the effects of release positions on the control of T. urticae. Overall, A. womersleyi was higher in its density and controlled the population of T. urtice. The control was better in the plots where A. womersleyi was released into the canopy or canopy and ground cover than in the plots where A. womersleyi was not released or released into the ground cover. Also, A. womersleyi established its population on the ground cover more quickly in the canopy and ground cover release plot than in other plots. Initial settlement of A. womersleyi was important to control T. urticae in the pear orchard. The abundance of T. urticae was critical for the initial settlement of A. womersleyi regardless of release rates.