The invention provides a submarine power cable with an insulating composite layer. The submarine power cable sequentially comprises a cable conductor, a metal jacket, a reinforced layer, a polyethylene jacket, a copper strip lapped layer, an armor layer and an outer coating layer from an inner layer to an outer layer, and further comprises the insulating composite layer. A central oil passage is formed in the cable conductor, radial cross-section sides of the reinforced layer and the armor layer are in pup joint with each other, and the insulating composite layer is arranged between the cable conductor and the metal jacket and structurally comprises an insulating material layer and an insulating shielding layer. The submarine power cable has the advantages that the pressure-resistant insulating composite layer with an excellent electric insulating property is additionally arranged between the cable conductor and the metal jacket and is made of nanometer modified epoxy resin and other components such as methyl tetrahydrophthalic anhydride and Qishi toughening agents by means of compounding, and accordingly the temperature-resistant and pressure-resistant performance, the mechanical strength and the insulating property of the submarine power cable can be greatly improved under synergistic effects of the nanometer modified epoxy resin and the other components.