Reversal of magnetization M by an electrical field E has been a long-sought phenomenon in materials science because of its potential for applications such as memory devices. However, the phenomenon has rarely been achieved and remains a considerable challenge. Here we report the large M reversal by E in a multiferroic Ba0.5Sr1.5Zn2(Fe0.92Al0.08)(12)O-22 crystal without any external magnetic field. Upon sweeping E through the range of +/- 2 MVm(-1), M varied quasi-linearly in the range of +/- 2 mu(B) per f.u., resulting in the M reversal. Strong electrical modulation of M at zero magnetic field were observable up to similar to 150 K. Nuclear magnetic resonance measurements provided microscopic evidence that the electric field and the magnetic field play equivalent roles in modulating the volume of magnetic domains. Our results suggest that the soft ferrimagnetism and the associated transverse conical state are key ingredients to achieve the large magnetization reversal at fairly high temperatures.