The invention discloses a medium-pressure torsion-resistant power cable. The power cable comprises at least one power cable core, at least one grounding cable core twisted with the power cable core, and a sheath layer wrapping the power cable core and the grounding cable core, wherein the power cable core comprises a conductor and an insulating layer covering the conductor; the insulating layer comprises the following components: ethylene propylene diene monomer rubber, microcrystalline wax, paraffin oil, antimony trioxide, titanium dioxide, nano zinc oxide, calcined kaolin, a coupling agent,an anti-aging agent, a vulcanizing agent and a vulcanizing assistant; and the sheath layer comprises the following components: chlorinated polyethylene, magnesium hydroxide, white carbon black, modified calcined kaolin, a thermoplastic elastomer, the anti-aging agent, red lead masterbatch, the antimony trioxide, light magnesium oxide, a calcium-zinc stabilizer, stearic acid, high-wear-resistant carbon black, a plasticizer, a cold-resistant plasticizer, the coupling agent, the vulcanizing agent and a vulcanization accelerator. The problem of the reduced service life of the torsion-resistant power cable of the 8MW offshore wind generating set due to long-term high-load flow, bending fatigue, aging, tearing and the like can be solved.