Spatial electronic scanned low- coherence interference long distance optical fiber sensing and demodulation system is investigated based the superluminescent light emitting diode (SLED). The compact beam path of demodulation interferometry is built by negative lens. The influence of the double SLED light sources power ratio on low-coherence interference fringe is analyzed and the power ratio compensation for transmission loss is discussed. According to the characteristics of double SLED light sources interference fringe, a double-threshold demodulation algorithm is proposed and a pressure demodulation experiment is conducted. Experimental results show that, in the pressure range from 50 kPa to 180 kPa, the demodulation precision of 0.24% to 0.40% F.S. is realized, where F.S. is full scale, and that the longest distance can reach 1.76 km. The results are in good agreement with the theoretical analysis.