Eriophyoid mites from Qinghai Province, northwestern China were studied herein. Up to now, only six species have been reported from Qinghai Province. In field surveys, 17 eriophyoid mite species were collected, among which nine species were found new to science. The new species and their host plants are listed as follows: Acaphyllisa tuberculumae sp. n. on Populus sp. (Salicaceae); Proiectus xiningensis sp. n. on Pinus sp. (Pinaceae); Phyllocoptes beishaniensis sp. n. on Spiraea mongolica Maxim. (Rosaceae); Tetra pruniana sp. n. on Prunus tomentosa Thunb. (Rosaceae) Rupr. (Berberidaceae); Tetra pyriana sp. n. on Pyrus calleryana Decne. (Rosaceae); Tetra simonia sp. n. on Populus simonii Carr. (Salicaceae); Diptacus berberinus sp. n. on Berberis amurensis Rupr. (Berberidaceae); Diptacus mengdaensis sp. n. on Lonicera elisae Franch. (Caprifoliaceae); Rhyncaphytoptus spinus sp. n. on Lonicera rupicola Hook. f. et Thoms. (Caprifoliaceae). Aculops ulmi Hong & Xue, 2005 was re-described.