Abstract:In this study, by gradually reducing the kinds of the trace elements and growth factors from the minimal medium of Pichia pastoris, the result showed that to maintain the normal growth of P. pastoris on agar plate, trace elements and growth factors except biotin don’t need to be added specially. A simplified minimal medium of P. pastoris, SPMD was presented, containing six kinds of inorganic salt, biotin and glucose. All components can be sterilized by autoclave except glucose which should be sterilized separately. This medium was used in screening for transformants and got a transformation rate comparable to that using MD medium.