Abstract: Liquid metal embrittlement (LME) of a 1.4 mm-thick galvanized 10Mn steel was investigated using a Gleeble 3500 thermal simulation tester. The fracture mode and failure behavior of galvanized 10Mn steel under different tensile temperatures (500 ℃-1000 ℃), tensile strain rates (10^-3 s^-1 -1 s^-1) and holding time (0 s-320 s) were analyzed. It is found that when the strain rates are 1 s^-1, 10^-1 s^-1 and 10^-2 s^-1, the temperature ranges of LME in 10Mn medium manganese steel are 700 ℃-950 ℃, 700 ℃-950 ℃ and 800 ℃-950 ℃, respectively. With the decrease of strain rate, the starting temperature of LME became higher and the temperature window become narrower. When the strain rate is reduced to 10^-3 s^-1, the LME does not occur. With the extension of holding time, the plasticity of galvanized 10Mn steel gradually recovers, and the LME can be eliminated by holding at 800 ℃ for 240 s and more, for the reason that the zinc layer reacts with the steel plate matrix and forms α-Fe(Zn) solid solution layer. SEM, EDX and EBSD analysis show that the fracture surface produced in contact with liquid zinc presents a typical brittle fracture surface, while the fracture surface without contact with liquid zinc is a dimple surface typical of ductile fracture. There is zinc distribution in the cracks tips and most of the cracks propagates along grain boundaries.