Abstract: To address the problem that conventional electro-hydraulic proportional valves cannot be applied to deep-sea hydraulic equipment under deep-sea high-pressure and strong-corrosion environments, this paper carries out structural improvement design for proportional valves to support the research and development of deep-sea cable-laying equipment. Firstly, the multi-way valve is sealed inside a pressure-tight chamber filled with hydraulic oil, and a compensator is adopted to balance the internal and external pressures. Meanwhile, a novel electro-proportional multi-way valve （hereinafter referred to as the multi-way valve） is developed. On the basis of conventional proportional valves, a wet-type electromagnet is adopted to realize the pressure-resistant design of the electromagnet. Secondly, oil-guide holes are machined inside the valve body and around the electromagnet to balance the internal and external pressures of the valve body and the electromagnet, so as to realize reliable operation of the multi-way valve under high-oil-pressure working conditions. Finally, pressure is applied to the sealed chamber to investigate the working performance of the multi-way valve under simulated deep-sea high-pressure conditions. The test results show that under an oil pressure of 10 MPa, the multi-way valve delivers stable output flow for each section, the flow hysteresis is approximately 10%, and the current signal maintains a good linear relationship with the flow of each section, which meets the control-accuracy requirements of the hydraulic system for multi-way valves.