A wide-band, polarization-insensitive and wide-angle metamaterial absorber based on loaded magnetic resonator is proposed. A single unit cell of the absorber is comprised of a magnetic resonator loaded with lumped elements, a substrate and a back metal board. Simulated absorbances of the one-dimensional-array absorber under loading and unloading conditions indicate that compared with under the unloading condition, the one-dimensional absorber under the loading condition can realize a wide-band absorption. Simulated absorbances of the one-dimensional-array absorber with lossy and loss-free substrates indicate that the power loss in the absorber results from lumped resistances in magnetic resonators, and is insensitive to the loss of the substrate. Simulated absorbances of the one-dimensional-array absorber with different lumped resistances and capacitances indicate that there exist optimal values for lumped resistances and capacitances, where the absorbance is highest and the bandwidth is widest. Simulated absorbances of the two-dimensional-array absorber under different polarization angles and different incident angles indicate that the absorber is polarization-insensitive and angle-wide.