ABSTRACT This article offers a novel study on the impacts of magnetic field and Soret-Dufour numbers on the thermosolutal convection of sloshing four fins on the wall sides of a square cavity occupied by a nanofluid. The incompressible condition of smoothed particle hydrodynamics (SPH) entitled ISPH method simulated sloshing four fins inside a nanofluid flow contained by a square cavity. The scales of pertinent parameters are fin length 0.05 ≤ L Fin ≤ 0.3 , Dufour number 0 ≤ Du ≤ 1 , a magnetic field inclination angle 30 ∘ ≤ γ ≤ 90 ∘ , Soret number 0 ≤ Sr ≤ 2 , Hartmann number 10 ≤ Ha ≤ 50 , Rayleigh number 10 4 ≤ Ra ≤ 10 7 , and nanoparticle parameter 0 ≤ ϕ ≤ 0.2 . The simulations of the ISPH method indicated the significant role of the fin’s length in enhancing the nanofluid alterations and transmission of thermal/solutal convection inside a cavity. Besides, the Rayleigh number has a great influence on improving nanofluid velocity and power of temperature/concentration. The Soret/Dufour numbers are successful in boosting the nanofluid speed as well as heat and mass transport, while the Hartmann number and nanoparticles parameter are effective in reducing the nanofluid movements.