The present invention provides a bisindole alkaloid compound or a pharmaceutically acceptable salt thereof, and a preparation method and an application thereof. The compound has a structure represented by formula (I) shown in the description; and in the formula, R1 is selected from hydrogen, a hydroxyl group, COOR', a C1-10 alkoxy group, a C2-10 alkenyloxy, a C2-10 alkynyloxy group and a halogen atom, the hydroxyl group can be substituted with a C1-10 alkoxy group, a C2-10 alkenyloxy group, C2-10 alkynyloxy or a halogen atom when the R1 is the hydroxyl group, R3 is selected from hydrogen or COOR', R2, R4 and R5 are respectively independently selected from hydrogen, a hydroxyl group, a carbonyl group, a C1-10 alkoxy group, a C2-10 alkenyloxy group and a halogen atom, R' is selected a C1-10 alkyl group, a C2-10 alkenyl group and a C2-10 alkynyl group, and the halogen atom is preferably fluorine, chlorine, bromine or iodine. The bisindole alkaloid compound of the formula or the pharmaceutically acceptable salt thereof has an amyloid protein-beta inhibition activity, and also has an activity of inhibiting podocyte injuries caused by high sugar.