We theoretically and experimentally study the effects of Faraday rotation, optical polarization of self-rotation, and their overlapping rotation. In our theoretical simulation, we set up a simple and effective theoretical model for the three kinds of rotations. In our experiment, the atomic vapor is placed in a magnetic shielding cavity to shield the earth magnetic field. Doppler-free spectrum configuration is used and the F=2 F'=3 transition of 87Rb D2 line is chosen. We observe the three kinds of rotations, separately. Experimental results and theoretical simulations are in good agreement.