Low freezing point ethylene glycol alkyl (C12-14) ether glycidyl ether (EGAGE) was synthesized based on C12-14 alcohol, ethylene oxide and epichlorohydrin. The epoxy value, viscosity and freezing point of EGAGE are 0.28 mol/100g, 14 mPa·s (25 °C) and -6.9°C, respectively. The structure of the product was characterized by FT-IR and 1H-NMR. A detailed comparative analysis was carried out with the commercially available reactive diluent alkyl (C12-14) glycidyl ether (AGE), and the basic performance indicators, the viscosity reduction effect on bisphenol A epoxy resin (DGEBA), and the cured products were investigated. The mechanical properties, thermal stability, chemical resistance and effects on the properties of epoxy syntactic foams were studied. The mechanical properties test shows that compared with pure DGEBA, when EGAGE was incorporated into DGEBA at 10%, the flexural strength, impact strength and elongation at break of the cured product are increased by 11%, 72% and 16%, respectively. SEM test shows that the fracture mode of the cured product mixed with diluent is ductile fracture, and the toughening effect is good. The results of thermogravimetric mass loss and chemical resistance test show that EGAGE/DGEBA has the better thermal stability and chemical reagent resistance. The epoxy syntactic foam with EGAGE (EGAGE/ESF) has a density of 0.798 g/cm3 and specific strength of 102.41 N·m/kg. And EGAGE/ESF has the advantages of small density, low water absorption and high specific strength, and shows a great application potential in the field of lightweight composite material.