In the real oceanic environment, seawater exhibits stratification. The temperature, salinity, and density of seawater all vary with depth. Among these, temperature and salinity are the fundamental variables that jointly determine density and describe the basic properties of seawater. They have significant impacts on mixing, turbulence, vortices, and other phenomena, serving as crucial analytical indicators for conducting other marine research. This study considers the dual influence of temperature and salinity on density, simulating a linearly stratified flow field driven by both factors. Taking the MARIN 7371R propeller as the research object, numerical simulations and studies were conducted on its propeller performance in both homogeneous fluid and linearly stratified fluid influenced by the dual factors of temperature and salinity, yielding the propeller's hydrodynamic parameters. A comparison is drawn between stratified fluids and homogeneous fluids in terms of thrust coefficient, torque coefficient, and open water efficiency, highlighting the unique properties of stratified fluids. It is found that the density stratification changes the pressure distribution around the propeller and increases the thrust of the propeller. In addition, the buoyancy effect of density stratification inhibits the vertical dissipation of the vortex generated by the propeller, thus enabling it to be significantly prolonged in the horizontal direction.