The self-mixing interference of orthogonal polarized o-light or e-light coming from a frequency splitting He-Ne laser was experimentally studied.First,the feedback curve is measured only if o-light or e-light existed in the equal intensity point.Second,the feedback curve is measured only when o-light or e-light existed in o-light is stronger than e-light.Finally,the feedback curve is measured only if o-light or e-light existed in e-light intensity is stronger than o-light.In one period,the amplitude of feedback curve measured in the experiment is two times bigger than that of the ordinary feedback curve.If this feedback technique can be used in measuring fields,the axial resolution can be effectively improved.