Low reflection material is very useful in many applications. At present, the operation frequency in the most absorbing materials are above 4 GHz, for it is difficult to realize the low reflection below 4 GHz with thin structure. A thin structure material that realize the low reflection was studied by using the analog circuit method in this issue. A genetic algorithm is used to find the optimization parameter. The simulations by equivalent circuit and FEM methods show a low reflection between 2 GHz and 9 GHz, which is only 9 mm thick and the value of reflection loss is lower than -6 dB.