In this article, mesoscopic approach has been utilized to investigate magnetic field impact on CuO-H2O nanofluid free convection inside a porous cavity with elliptic heat source. Simulations have been done via LBM. KKL model is employed to consider Brownian motion impact on nanofluid properties. Influences of Rayleigh number (Ra), nanofluid volume fraction (phi), Hartmann number (Ha), Darcy number (Da) on heat transfer treatment are demonstrated. Outputs demonstrate that temperature gradient reduces with increase of Ha while it increases with augment of Da,Ra. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.