The composition of the angle random walk in the four-mode ring laser gyro (RLG) has been researched. It escapes the trouble from the type of random walk caused by crossing the dead band contained in the dithered RLG. By changing the current of the gyro, the time order pulse output of the gyro in different laser intensities is measured. Then the random walk coefficients of the corresponding laser intensities are calculated. According to the feature of the quantum noise, the random walk can be separated into two parts: the random walk due to spontaneously emitted photons and the random walk due to other causes. The experimental results show that the random walk due to other causes plays a more important role in the current status of technology. If the part of random walk could be eliminated or weakened, the value of the random walk would be reduced, and the performance of the gyro would be improved.