To reseach technology of the potato yogurt，the technology and formulation of potato yogurt inoculation of the ferment,fermentation time,temperature and other parameters were studied. The optimum technological conditions of potato yogurt were optimized.The optimum formulation was as followed: potato juice to milk 20∶70(V∶V), sugar 4%(m/V), Starter cultures 8%（V/V）, ferment time 6 h.