In order to improve the accuracy of interference of Fourier transform infrared spectrometer, we design an automatic regulating system based on integrative beam splitter.　Using optical glue to fix the prism and beam splitter.　Three adjustment structures was set on the integrative beam splitter. The O point is fixed as the reference point, and piezoelectri ceramics are loaded on the X point and Y point.Using the piezoelectri ceramics to drive beam splitter for tiny displacement adjustment.When the moving mirror moves in constant speed, using four quadrant detector to test the phase difference of three signals.　Then three signals are enlarged, filtered and digitized.　Using the ECAP of DSP to catch three signals and Using the increment PID to conduct real time control the adjustment of three signals based on phase difference. These three signals is sampled by the AD of DSP.　All the information measured can communication with the host PC through USB2.0, then finally reading collection data and real-time demarcating the wave show.　The ultraviolet radiator is installed on the holder, the irradiation of ultraviolet light on optical glue is increased when the ajustment start.　So that the integrative beam splitter is made which can meet the demand of fourier transform infrared spectrometer.　The experimental results show that the design of automatic regulating system based on integrative beam splitter has advantages of simple structure, high adjustment accuracy which can meet the demand of common infrared beam splitter.