Salt content detection sensors are of great significance for the rapid and accurate detection of solution salt content, especially for monitoring the salt density of external insulation in power equipment athigh altitude complex environments. However, the traditional method usually hasthe shortcomings of complex operation, long detection time, and low sensitivity, which makes it difficult to meet the needs of modern industrial production. To improve this problem, we propose a novel surface plasmon resonance (SPR) sensor that combines the advantages of bimetallic layers of gold (Au) and silver (Ag) with the unique properties of two-dimensional materials MXene, tungsten disulfide (WS₂) and black phosphorus (BP), such as high electrical conductivity, hydrophilicity, excellent thermal stability, and adsorption capacity. By optimizing the structure of each layer of the sensor and comparing the sensitivity of resonance spectra of different metal structures of the sensor, the results show that the bimetallic layer (Au/Ag)/MXene/WS₂/BP structure sensor has a sensitivity of up to 200°·RIU^-1. The sensor has a stronger detection ability, so it can accurately and quickly detect the salt content of the solution and provide strong support for environmental protection, resource utilization, and safety in production.