The invention provides a free microspore induced culture medium for brassica campestris. A formula of the culture medium contains KNO3, MgSO4.7H2O, KH2PO4, Ca(NO3)2.4H2O, Na2-EDTA, FeSO4.7H2O, MnSO4.4H2O, AgNO3, H3BO3, ZnSO4.7H2O, KI, Na2MoO4.2H2O, CuSO4 .5H2O, CoCl2.6H2O, chlorinated 2-hydroxyethyl trimethylamine, L-glutamine, vitamin B1, vitamin B6, nicotinic acid, folic acid, biotin, inositol, glycine, L-glutathione, methyl nitrosourea, sucrose, phytagel, 6-BA, NAA, polyethylene glycol, protein hydrolysate, active carbon and phytosulfokine PSK-alpha. The culture medium can be used for greatly improving the induction efficiency of free microspore embryogenic calli of brassica campestris, and has an important application value.