A dihydropyridine (DHP) calcium antagonist compound and its preparation method and medical use are related to preparation methods of compounds of general formulas (I) and (II) as shown below and their pharmaceutical salts and applications for treating cardiovascular diseases, and R1 represents a substituted or unsubstituted heterocyclic, aromatic ring or aralkyl group, and the substituent may be C1-C4 alkyl, C1-C4 alkoxyl, halogen, cyano, trifluoromethyl, trifluoromethoxyl, methylthio, nitro, amino or hydroxyl group; R2 represents a C1-C8 alkyl group; R3 and R4 are the same or different, and each represents a hydrogen, halogen, cyano, trifluoromethyl, trifluoromethoxyl, methylthio, nitro or amino group or a C1-C4 alkyl, C1-C4 alkoxyl, C1-C4 alkenyl, or C1-C4 alkinyl group; R5 and R6 are the same or different, and each represents a C1-C4 alkyl group; X represents O, S or a single bond; m=0-6, n=1-6, and m and n are the same or different.