A liquid molding compound for protecting five edges of a semiconductor chip and a preparation method thereof are disclosed. The liquid molding compound includes 15 to 40 parts by mass of an epoxy resin, 15 to 35 parts by mass of a curing agent, 0.1 to 3 parts by mass of a curing accelerator, 4 to 15 parts by mass of a toughening agent, 75 to 150 parts by mass of an inorganic filler, and 0.1 to 5 parts by mass of a coupling agent. The epoxy resin is one or more selected from the group consisting of a bisphenol A epoxy resin, a bisphenol F epoxy resin, and a biphenyl epoxy resin. The toughening agent is an adduct of an epoxy resin and a carboxyl-terminated liquid butyronitrile rubber, and the curing agent is a phenol-formaldehyde resin. The molding compound has a low coefficient of thermal expansion (CTE).