Optical Frequency-Domain Reflectometry (OFDR) is appropriate for the measurement of rapid changing micro space quickly and high-accuracy especially for the turbine blade tip clearance. The principle of OFDR measurement system is analyzed and the real time demodulation algorithm of spectral interferometry signal is designed. Demodulating, displaying and controlling of the signals in real time from the measurement system are realized based on LABVIEW data flow diagram. Experiments show that the algorithm and LABVIEW platform function are reliable and available for engineering application.