During the real-time interferometry, the phase measurement error may be caused by any of the ambient temperature fluctuation and air turbulence and the drift of the system inner parameters, especially in high-accuracy survey occasion,the influence of this error is especially obvious. Therefore, this paper put forward a filtering phase discrimination LD real-time SPM surface profile interferometry insensitive to disturbance, clarified their operating principle. This feedback control system takes out the interference signal of one measured point from the total interference signal as a feedback signal, then injects it into the semiconductor laser to make its wavelength change. So the phase error caused by external interference is reduced to the negligible degree, and the influence to the measurement accuracy caused by external interference is sharply reduced. And the normalization technology is used to eliminate the influence to the measurement accuracy caused by system inner parameters’ drift . For 70×70 measured points, its repeatable measurement precision is about 3 nm , measuring time is less than 12 ms.