Abstract: The self-mixing interference of orthogonal polarized lights coming from a frequency splitting He-Ne laser is experimentally studied. Owing to mode competitive effects between orthogonal polarized o-light and e-light,maximum of the o-light is corresponding to minimum of the e-light in the feedback curve of the o-light and e-light,or vice versa. In a period,the maximum appears two times when the maximum of the general feedback curve appears one time,and the amplitude also changes two times.