The invention discloses an epoxy resin composition, a metal-based copper-clad plate and a manufacturing method thereof. The epoxy resin composition comprises the following components by mass: 90-110 parts of epoxy resin, 10-50 parts of thermoplastic resin, 1-100 parts of a curing agent, 0.05-5 parts of a curing accelerant, 1-10 parts of an additive, 20-500 parts of heat conduction filler and 0-30 parts of an organic solvent. The metal-based copper-clad plate has the characteristic that 1, the heat conductivity is high; 2, the insulation property is high as the puncture-withstand voltage is higher than 6KV; 3, the anti-bending property is high, so that the metal-based copper-clad plate can be used for manufacturing a three-dimensional aluminum substrate; 4, the thickness of the insulation layer is uniform, the coating thickness tolerance can be controlled at +/- 2 microns, and the press-fit thickness tolerance can be controlled at +/- 5 microns, so that the performance of a product can be guaranteed; 5, the production efficiency is high; 6, the cost is low and is about 1/4-1/3 of the cost of an imported product.