Abstract: Effect of the trace elements,including the growth factors,precursors and cations,on the production of Monacolin K and Lovastatin in the liquid fermentation of Monascus was studied.The secondary metabolites of the acidic form of Monacolin K and the lactone-form of Lovastatin were measured by using HPLC.The results showed that the addition of vitamin B3 as a growth factor,sodium acetate as a precursor and Zn2+as a cation significantly increased the total yield of Lovastatin and raised the proportion of Monacolin K produced in the liquid fermentation of Monascus.Based on the orthogonal test,the optimized additions of these trace elements were found to be 0.15%ZnSO4,0.01% vitamin B3 and 0.15% sodium acetate.The resulting total Lovastatin production was 57.138mg·L-1,the acidic form of Monacolin K was 44.958mg·L-1,and the proportion of the acidic form of Monacolin K increased to 79% of the total Lovastatin collected.