Abstract: The forced convection and the heat transfer feature of Cu-H₂O nanofluids in two dimensional channel is studied by Lattice Boltzmann method(LBM), and the effects of volume fraction(φ), relative roughness(ε), Reynolds number(Re) of the Cu nanoparticle in microchannel on the fluid flow and heat transfer are analyzed.Resultsshow that when the wall surface is smooth, with the increase of Re at the entrance, the Nu_ave at the wall increases, and that with the increase of volume fraction φ, the Nu_ave also increases; when the wall surface is tough, with the increase of Re at the entrance and volume fraction φ, the Nuave at the wall increases, but the increment is less than that when the wall surface is smooth. Besides, with the increase of relative roughness ε, the Nu_ave decreases.