A new species of ptyctimous mites of the genus Arphthicarus (Oribatida, Steganacaridae) is described from the litter in East Tibet, China. Arphthicarus olszanowskiisp. nov. differs from Arphthicarus indicus (Bayoumi et Mahunka, 1979) by prodorsal lateral carinae absent, lamellar setae longer than half length of interlamellar setae, vestigial notogastral setae present, mentum setae h<h–h, formula of genital setae 7(4+3): 2, and setae ad₃ much shorter than ad₂. A key to all known species of Arphthicarus from the Palaearctic and Oriental Regions is proposed to facilitate further studies of this group.