The effects of fly ash content and early curing temperature on the tensile properties and microstructure of engineering geopolymer composites （EGC） were studied. The mechanical properties of fiber-matrix interface of EGC were analyzed from the perspective micromechanics. The test results show that the decrease of fly ash content is not conductive to the improvement of the tensile ductility of EGC， and the moderate increase of early curing temperature is conducive to the improvement of tensile properties of EGC. When the fly ash content is 80%， and the early curing temperature is 60 ℃ or 80 ℃， the tensile strain of EGC can reach more than 3.5%. The longer slip hardening stage during fiber pullout process is helpful to improve the tensile performance of EGC.