Abstract: Orthogonal test was used to optimize key factors of mother culture media that affecting the growth of mycelia.The results showed that the best carbon nitrogen ratio was 15:1 and the optimum pH for 5; the best pine sawdust leaching liquid adding amount was 40%; the optimal inorganic salt was magnesium. The best formula was carbon nitrogen ratio 17:1, pH 5.5 and pine sawdust leaching amount was 35%.