In this paper, numerical simulation is conducted to study the effect of wall temperature variation on MHD nanofluid of CuO/water. The continuity, momentum and energy equations are discretised with finite volume technique and SIMPLE method was applied for dealing velocity and pressure field. Rie and Chow method was used to handle the checker board problem of pressure field. It was observed that Nu reduces 30% by increasing the frequency from 0.5 Hz to 2 Hz and then enhances 35%with increasing frequency from 2 Hz to 8 Hz. The Nu is strongly influenced by frequency more 1 Hz.