Magnetic NiSO4/gamma-Al2O3 catalysts were prepared by impregnating NiSO4 solutions onto the gamma-Al2O3 support containing a magnetic material of Fe3O4. Characterization by XRD, NH3-TPD, and thermal analysis showed that the magnetic NiSO4/gamma-Al2O3 catalyst with a nickel content of 7.0% by weight had a monolayer dispersion of NiSO4 and the largest number of moderate strength acid sites, and a high specific saturation magnetization. The magnetic catalyst was evaluated for light FCC gasoline olefin oligomerization in both fixed-bed and magnetically stabilized bed (MSB) reactors. Comparing with that in the fixed-bed reactor, the optimal reaction temperature in the MSB lowered to 443 K, and its space velocity ranged broadly from 2.0 to 6.0 h(-1). The sulfur-free diesel distillate produced by operation of the MSB for 100 h had higher cetane number and good low-temperature flow property, which illuminates a promising application of the MSB to manufacture clean diesel fuels with high productivity and flexibility. (c) 2009 American Institute of Chemical Engineers AIChE J, 55: 717-725, 2009