The invention discloses a semi-locking type steel wire armored submarine power cable and a design method thereof. The cable comprises a copper conductor, a conductor shielding layer, an insulating layer, an insulation shielding layer, a semi-conductive water-blocking tape, a lead sleeve, an MDPE sheath, a non-woven fabric, a first PP rope, an armor and a second PP rope. The armor is composed of steel wires and PE pipes, the steel wires and the PE pipes are arranged in a one-spacing-one mode, the steel wire is in an I shape, and arc grooves are formed in the side faces of the steel wires. In the way, according to the semi-locking type steel wire armored submarine power cable and the design method thereof, the cable manufactured through the design method solves the problems that a circular steel wire armored structure is prone to loosening after being damaged due to stress and is not prone to being fished out in seawater, reassembly is carried out through disassembling and replacing thePE pipe for maintenance, and the problem of later operation and maintenance difficulties are improved.