Four new eriophyoid mite species (Acari: Eriophyoidea: Diptilomiopdiae) from Hainan Province, China are described and illustrated. They are Diptilomiopus diaoluoicus sp. nov. on Eurya hainanensis (Kobuski) H. T. Chang (Theaceae), Diptilomiopus engelhardter sp. nov. on Engelhardtia roxburghiana Wall. (Juglandaceae), Neorhynacus altingus sp. nov. on Altingia obovata Merr. et Chun (Hamamelidaceae); Konola pingis sp. nov. on Machilus pingii Cheng (Lauraceae). All the new species described herein are vagrants on the host plant.