In this work, a stable NiFe2O4 paraffin based ferrofluid was prepared via high energy milling. The rheological properties of ferrofluid were studied. Bingham plastic, HerschelBulkley and Casson models were used to evaluate the shear stress-shear rate dependency. The ferrofluid exhibited a shear thinning behaviour for all studied magnetic field. The magneto-viscous effect and thixotropy of ferrofluid were studied and the role of formation and destruction of magnetically induced structures and the interactions of nanoparticles and aggregates were discussed.