In this paper we show effective thermal conductivity enhancement of spherical nanoparticles for use in fluid suspensions in microchannels with increase nanolayer thicknesses. For laminar flow, as effective thermal conductivity increases with increasment of nanolayer thickness, Nusselt number decreases. Also the effect of nanolayer thicknesses with increasment of nanoparticle volume fraction is considerable. We present the effect of nanolayer on microchannel thermal resistance for various pumping power.