A structure of matematerial absorber constructed based on lumped elements is proposed, analyzed theoretically and verified experimentally. The simulated results indicate that the absorption of the proposed absorber is over 95% in the frequency range of 2.5 to 4.46 GHz, and the FWHM is 70.4%. The designed structure has a better impedance matching characteristic to the free space in a wider frequency range when loaded with lumped elements by scattering parameter retrieval calculation. It also can be found that the large loss occurs in lumped resistance, which contributes much to the low-frequency broadband absorption properties obtained by simulating the energy loss distribution of the dielectric surface. Results measured by means of the free space method agree well with the simulation. Further measured results also show that the thickness of FR4 substrate obviously has controllable effects on absorption properties of the absorber, the absorption wide band will move to lower frequency with the increase of thickness, and the optimal thickness for the structure of certain parameters also can be obtained.