Abstract: In the case of the reverberation chamber (RC) with reflectors in it, the effect of the change of the reflectors on the characteristics of the field in RC is researched. On the basis of the microwave chaotic theory, the distribution of the field in unregular cavities is studied. Then the methods to judge the field uniformity and isotropy in the RC are established according to the statistical electromagnetics. The influences of the size, the number and the distribution of the reflectors in the RC on the field uniformity are studied. Simulation results show that the bigger the reflector is, the greater the influence on the field will be. The uniformity and isotropy are both improved as a result. Moreover, increasing the number and enlarging the range of the reflectors are helpful to decrease the standard deviation of the field, which means the improvement of the uniformity of the field and the harmonicity of the energy.