A tunable metamaterial absorber with a W/VO2 square lattice nanostructure is designed and fabricated. With the excitation of plasma resonance, the tunable mechanism is achieved by the phase transition of vanadium dioxide. The optimal parameters are analyzed by using a finite difference time domain simulation method. The close-to-one absorption peak occurs around a wavelength of 5.28 mu m, at which the difference of absorption between high and low temperatures is 89.74%. The findings also show that the absorber is polarization-independent and exhibits wide-angle absorption. The experimental results are in good agreement with the simulation. The results of this study show great potential for the application of energy and sensing metamaterial absorbers.