In this research, the combined convective-radiative heat transfer for magnetohydrodynamics (MHD) hybrid nanofluid flow inside an open trapezoidal enclosure are numerically simulated. There are two diagonal side walls and a horizontal wall defining this open enclosure. This enclosure's inclined side walls are accurately modeled using the embedded boundary approach. Calculations of thermal radiation term in the energy equation are done based on the Roseland approximation. The nanofluid applied in this research is a mixture of hybrid Al2O3-CuO nanoparticles and H2O base fluid. To investigate the thermal treatment, distributions of dimensionless temperature in the enclosure and the variations of Nusselt numbers on its bottom hot wall are presented for various magnitudes of radiative parameter, hybrid nanoparticles volume fractions and magnetic force. The obtained findings indicate the highest magnitude of total heat transfer rate on the enclosure bottom hot wall is registered in absence of magnetic force Ha=0 and for highest values of radiative parameter Rd=1 and hybrid nanoparticles concentration ϕ=0.03Al2O3+0.03CuO.