The morphological ontogeny of Diapterobates altaicus Bayartogtokh, 2010 is described and illustrated. The juveniles of this species are unpigmented, except for a dark sclerite around a gland opening on the hysterosoma. In the larva, most gastronotal setae are of medium size, except for longer c₃, dp, lm, lp and h₁, whereas in the tritonymph, all gastronotal setae are long, especially c₃, dp, lp, h-series and p₁. In all juvenile stages, a humeral organ is present. The adult of D. altaicus has setae bv″ and v″ on femur I clearly shorter than seta d.