This paper studies the microstructure of Zeron100duplex stainless steel by using electronic backscatter diffraction (EBSD) technology. When using EBSD to rapidly identify Zeron100duplex stainless steel and analyze the phase distribution in heat treatment, it is found that as the hot-exposed time goes on (the heating temperature is 850℃), the ferrite materials in content decreases and brittleness intermetallic increases, thus improving the brittleness material and reducing corrosion resistance. Moreover, EBSD is used to analyze the orientation relationship between austenite and ferrite of Zeron100duplex steel. It shows that the two phases accord with Kurdjumov-Sachs (K-S) orientation. Deviation distributes from 0~4degrees, with the most concentrates in 1~2degrees. The analysis result and the theoretical calculation results are in good conformity.