The radiation trapping is an important dispersion effect which can greatly affect the performance of laser gyro. Focusing on the defects of previous methods, new correction methods are presented. Based on the strict analysis of the radiation trapping physical process, the correction formula of two frequency laser gyro is presented, which can solve the defects in the Aronowitz’s method. Based on the strict analysis of mode coupling effects in four mode lasers, the correction formula of four frequency laser gyro is presented, which is in accordance with the physics essence well. It is helpful to the theoretical research on laser gyro.