The numerical solution fitted of the electrical-conductance fluid flow with low Reynolds number and low Hartman number in the channel with unsymmetrical cavity is described. The method of finite differences is used to solve the MHD Navier-Stokes equations for plane flow. The flow through channels with different dimensions of cavity is considered. The results of numerical investigations for Reynolds number Re less than equivalent to 50 and Hartman number H less than equivalent to 1,0 are shown in graphs of streamlines.