Abstract: The present paper reports the scanning electron microscopy observation on the ultrastructure of gnathosoma,podosoma and opisthosoma in the life cycle of Demodex caprae.The following were found:A cone-shaped palpal papillae was at dorsal side of palpal segment 2 in female;the lobe-like dorsal paramera and ventral paramera were on the base of aedeagus;the boat-shaped vulva was covered by a pair of valves meeting along the longitudignal line in virgin female;the genital was half opened after mating,and it was widely opened after laying egg.In addition,the ultrastructure of the supracoxal spines,the epistome,the hypostome,the chelicera,the coxal endite,the oral opening,the palpal claws and the proctodeum were described;the morphology of the ultrastructure observed were briefly compared with those of D.canis,D.folliculorum and D.brevis;the function of the epistome,the hypostome,the chelicera,the coxal endite,the palpal claws and the palpal papilla were discussed.