Abstract: Laser feedback interference has been the research highlight in the area of optical measurements, due to its advantages of common path and high precision. The measurements method of laser feedback interference was obtained according to the external reflective object’s information to analyze the characteristics of reflective light based on the basic theory and the main model of the laser feedback interference. Measurement of external reflective object’s information was realized through the analysis of laser output characteristics change. Laser feedback speckle interference was produced from the laser feedback interference and the laser speckle technology for the objects with the rough surfaces or the fluids. The phenomenon of multiple laser feedback interference arose from the laser feedback interference on condition of a short off-axis external cavity for the objects with smooth surfaces. The laser feedback interference technology achieved rapid development in the areas of displacement, angle, speed, imaging and so on for precisely detecting. The laser feedback interference technology was able to detect the weak feedback light scattered by the rough surfaces with high sensitivities and it also has the advantage of high precision like the traditional interference technology. The conclusion is drawn that the laser feedback interference technology has the research value and the application prospect in the fields of biological medicine for the non-contact detection.