A direct method for manufacturing a large model fractured core and maintaining original oil-water saturation, including the following steps: (1) determining the volume V, porosity φ, permeability K, oil saturation So, water saturation Sw and the like of a fractured core to be manufactured; (2) preparing simulated oil, and determining the used oil mass mo=Vo×ρo; (3) under the circumstance of no consideration of oil saturation, acquiring the mass of the used water, cement and quartz sand; (4) while establishing oil saturation, acquiring the mass mw of water for manufacturing the core as mw=a−Vo×ρw; (5) mixing oil, water and an emulsifier evenly to prepare an oil-in-water emulsion; (6) adding cement and quartz sand into the emulsion and stirring evenly to obtain cement slurry; (7) when a cement sample is in a semi-solidified state, cutting the cement sample with a steel wire; and (8) solidifying the cement sample to the end.