Starting from the two-conduction-band Anderson lattice model, the magneto-transport properties of heavy-fermion systems are studied in the slave-boson mean-field theory. The residual magnetoresistivities induced by different kinds of impurity are calculated, and the experimentally detected positive maximum structure in the residual magnetoresistance of heavy-fermion systems is reproduced. The transition of field-dependent resistivity from non-monotonic to monotonic behaviour with increasing temperature can be explained naturally by including the charge fluctuation effect. The influences of applied pressure are also investigated.