Effects of the dielectric loading on the transmission properties of frequency selective surfaces(FSS) were preliminarily explored by experiment, especially in the thickness, loading patterns of the dielectric and the sensitivities of the forementioned parameters to the varying angle of incidence. The experimental results show that the resonant frequency of FSS decreases with the dielectric loading, the transmission ratio and resonant frequency are changed with the different dielectric thickness, and the dielectric symmetrically loading can stabilize the FSS transmission characteristic as the angle of incidence is varied.