We examine the current-induced magnetoresistance oscillations in high-mobility two-dimensional electron systems using the balance-equation scheme for nonlinear magnetotransort. The reported analytical expressions for differential magnetoresistivity at high filling factors in the overlapping Landau-level regime, which show good agreement with the experimental observation and the numerical calculation, may be helpful in extracting physical information from experiments.In addition to the universally existing Shubnikov-de Haas oscillations (SdHO), many different kinds of magnetoresistance oscillations were discovered in the past few years in high-mobility two-dimensional (2D) electron systems (ES) subject to a weak perpendicular magnetic field and have become a field of great interest. These resistance oscillations always occur at low temperatures and are related to magnetotransport of 2D electrons occupying high Landau levels (LLs). Among them the microwave-induced magnetoresistance oscillations and the related zero-resistance states were the central focus of most experimental 1,2,3,4,5,6,7,8,9,10 and theoretical 11,12,13,14,15,16,17,18,19,20,21 studies. Recently, the oscillatory behavior in the nonlinear magnetotransport has attracted much attention: in a 2D system even without irradiation, a relatively weak current can induce drastic suppression and strong oscillations of the differential magnetoresistance, and may result in a state of zero-differential resistance. 22,23,24,25,26 Several theoretical models have been proposed in an attempt to explain this interesting nonlinear phenomenon. 27,28,29,30 Numerical examinations based on the current-control transport scheme were shown in good agreement with the experimental observation for differential magnetoresistivity as a function of the ratio of the current density to the magnetic field in both the magnetic-field sweeping and the current-sweeping configurations covering both separated and overlapping Landau level regimes. 27 It is reported recently that by a systematic analysis of current-induced magnetoresistance oscillations, important physical information about electron-electron interaction on the single particle life time can be extracted. 31 From the point of view of experiment, an analytical expression for differential magnetoresistivity, even applies only within limited ranges, is highly desirable because it can be of great help to extract important physical information from experimental data. So far, a reliable analytical expression derived from experimentally confirmed theoretical models is still lacking.We examine this issue based on the balance-equation scheme of nonlinear magnetotransport, 27 which deals with a 2D system consisting of N s electrons in a unit area of the x-y plane and subjected to a uniform magnetic field B = (0, 0, B) in the z direction. These electrons, scattered by randomly distributed impurities and by phonons in the lattice, perform an integrative drift motion under the influence of a uniform electric field E in the x-y plane. For h...